SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                  SCHEDULE 13G/A

                   Under the Securities Exchange Act of 1934*
                                (Amendment No.1)*


                                Lan Airlines S.A.
                                -----------------
                                (Name of Issuer)

                    Shares of Common Stock without par value
                    ----------------------------------------
                         (Title of Class of Securities)

                                 Not Applicable
                                 --------------
                                 (CUSIP Number)

                                    12/31/04
                                    --------
             (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

         |_|      Rule 13d-1(b)
         |_|      Rule 13d-1(c)
         |X|      Rule 13d-1(d)


*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).





-------------------------------
CUSIP No.     Not applicable          13G
-------------------------------


 1.  NAME OF REPORTING PERSONS
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

     Tres Mares S.A.

 2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*        (a) |_|
                                                              (b) |X|
 3.  SEC USE ONLY


 4.  CITIZENSHIP OR PLACE OF ORGANIZATION

     Chile

                  5.   SOLE VOTING POWER
NUMBER OF
SHARES                 23,480,593
BENEFICIALLY
OWNED             6.   SHARED VOTING POWER
BY EACH
REPORTING              - 0 -
PERSON
WITH              7.   SOLE DISPOSITIVE POWER

                       23,480,593

                  8.   SHARED DISPOSITIVE POWER

                       - 0 -

 9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     23,480,593

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_|

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     7.4%

12.  TYPE OF REPORTING PERSON*

     CO
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!






-------------------------------
CUSIP No.     Not applicable          13G
-------------------------------


 1.  NAME OF REPORTING PERSONS
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

     Boris Hirmas Said

 2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*        (a) |_|
                                                              (b) |X|
 3.  SEC USE ONLY


 4.  CITIZENSHIP OR PLACE OF ORGANIZATION

     Chile

                  5.   SOLE VOTING POWER
NUMBER OF
SHARES                 -0-
BENEFICIALLY
OWNED             6.   SHARED VOTING POWER
BY EACH
REPORTING              23,480,593
PERSON
WITH              7.   SOLE DISPOSITIVE POWER

                       -0-

                  8.   SHARED DISPOSITIVE POWER

                       23,480,593

 9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     23,480,593

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_|

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     7.4%

12.  TYPE OF REPORTING PERSON*

     IN
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!





-------------------------------
CUSIP No.     Not applicable          13G
-------------------------------


 1.  NAME OF REPORTING PERSONS
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

     Maria Pia Hirmas Said

 2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*        (a) |_|
                                                              (b) |X|
 3.  SEC USE ONLY


 4.  CITIZENSHIP OR PLACE OF ORGANIZATION

     Chile

                  5.   SOLE VOTING POWER
NUMBER OF
SHARES                 -0-
BENEFICIALLY
OWNED             6.   SHARED VOTING POWER
BY EACH
REPORTING              23,480,593
PERSON
WITH              7.   SOLE DISPOSITIVE POWER

                       -0-

                  8.   SHARED DISPOSITIVE POWER

                       23,480,593

 9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     23,480,593

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_|

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     7.4%

12.  TYPE OF REPORTING PERSON*

     IN
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!





-------------------------------
CUSIP No.     Not applicable          13G
-------------------------------


 1.  NAME OF REPORTING PERSONS
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

     Paola Hirmas Said

 2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*        (a) |_|
                                                              (b) |X|
 3.  SEC USE ONLY


 4.  CITIZENSHIP OR PLACE OF ORGANIZATION

     Chile

                  5.   SOLE VOTING POWER
NUMBER OF
SHARES                 -0-
BENEFICIALLY
OWNED             6.   SHARED VOTING POWER
BY EACH
REPORTING              23,480,593
PERSON
WITH              7.   SOLE DISPOSITIVE POWER

                       -0-

                  8.   SHARED DISPOSITIVE POWER

                       23,480,593

 9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     23,480,593

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_|

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     7.4%

12.  TYPE OF REPORTING PERSON*

     IN
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!





-------------------------------
CUSIP No.     Not applicable          13G
-------------------------------


 1.  NAME OF REPORTING PERSONS
     S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

     Emilia Said de Hirmas

 2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*        (a) |_|
                                                              (b) |X|
 3.  SEC USE ONLY


 4.  CITIZENSHIP OR PLACE OF ORGANIZATION

     Chile

                  5.   SOLE VOTING POWER
NUMBER OF
SHARES                 -0-
BENEFICIALLY
OWNED             6.   SHARED VOTING POWER
BY EACH
REPORTING              23,480,593
PERSON
WITH              7.   SOLE DISPOSITIVE POWER

                       -0-

                  8.   SHARED DISPOSITIVE POWER

                       23,480,593

 9.  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     23,480,593

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* |_|

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     7.4%

12.  TYPE OF REPORTING PERSON*

     IN
                      *SEE INSTRUCTIONS BEFORE FILLING OUT!





Item 1(a).    Name of Issuer:
---------     Lan Airlines S.A. ("Lan Airlines")

Item 1(b).    Address of Issuer's Principal Executive Offices:
---------     Avenida Americo Vespucio Sur 901, Comuna de Renca, Santiago, Chile

Item 2(a).    Name of Persons Filing:
----------


              This Statement is filed, pursuant to Rule 13d-1(k)(1) under the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), by the persons
listed below (the "Reporting Persons").

              (1) Tres Mares S.A.
              (2) Boris Hirmas Said
              (3) Maria Pia Hirmas Said
              (4) Paola Hirmas Said
              (5) Emilia Said de Hirmas

              As of December 31, 2004, Boris Hirmas Said, Maria Pia Hirmas Said,
Paola Hirmas Said and Emilia Said de Hirmas held their beneficial ownership
interests in Lan Airlines through Tres Mares S.A., which is a shareholder of Lan
Airlines.

              Tres Mares S.A. is owned by Boris Hirmas Said, Maria Pia Hirmas
Said, Paola Hirmas Said and Emilia Said de Hirmas.

Item 2(b).    Address of Principal Office or, if None, Residence:
---------

              (1) Avenida Vitacura 5093, Oficina 504, Santiago, Chile.
              (2) Americo Vespucio Norte 520, Oficina 202, Las Condes, Santiago,
                  Chile.
              (3) Americo Vespucio Norte 520, Oficina 202, Las Condes, Santiago,
                  Chile.
              (4) Americo Vespucio Norte 520, Oficina 202, Las Condes, Santiago,
                  Chile.
              (5) Americo Vespucio Norte 520, Oficina 202, Las Condes, Santiago,
                  Chile.


Item 2(c).    Citizenship or Place of Organization:
---------     See Item 4 on pages 2 through 6.

Item 2(d).    Title of Class of Securities:
---------     Shares of Common Stock without par value.

Item 2(e).    CUSIP Number:
---------     Not Applicable

Item 3.       Not Applicable
-------

Item 4.       Ownership:
-------

              (a)   Amount beneficially owned:
                    See Item 9 on pages 2 through 6.

              (b)   Percent of class:
                    See Item 11 on pages 2 through 6.

              (c)   Number of shares as to which such person has:

                   (i)   Sole power to vote or to direct the vote:
                         See Item 5 on pages 2 through 6.

                   (ii)  Shared power to vote or to direct the vote:
                         See Item 6 on pages 2 through 6.

                   (iii) Sole power to dispose or to direct the disposition of:
                         See Item 7 on pages 2 through 6.

                   (iv)  Shared power to dispose or to direct the disposition
                         of:
                         See Item 8 on pages 2 through 6.

Item 5.       Ownership of Five Percent or Less of a Class:
------        Not Applicable

Item 6.       Ownership of More than Five Percent on Behalf of Another Person:
------        Not Applicable

Item 7.       Identification and Classification of the Subsidiary Which Acquired
------        the Security Being Reported on by the Parent Holding Company:
              Not Applicable

Item 8.       Identification and Classification of Members of the Group:
------        Not Applicable

Item 9.       Notice of Dissolution of Group:
-------       Not Applicable

Item 10.      Certification:
--------      Not Applicable

         This filing amends the information previously filed by the Reporting
Persons on Schedule 13G on March 5, 2003.





                                    SIGNATURE

         After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

                                      TRES MARES S.A.

February 11, 2005                      By:  /s/ BORIS HIRMAS SAID
                                            ---------------------------
                                            Name:  Boris Hirmas Said
                                            Title: Legal Representative


                                       By:  /s/ BORIS HIRMAS SAID
                                            --------------------------
February 11, 2005                           Boris Hirmas Said


                                       MARIA HIRMAS SAID

                                       By:  /s/ BORIS HIRMAS SAID
February 11, 2005                           --------------------------
                                            Name:  Boris Hirmas Said
                                            Title: Legal Representative

                                       PAOLA HIRMAS SAID

                                       By:  /s/ BORIS HIRMAS SAID
February 11, 2005                           --------------------------
                                            Name:  Boris Hirmas Said
                                            Title: Legal Representative


                                       EMILIA SAID DE HIRMAS

                                       By:  /s/ BORIS HIRMAS SAID
February 11, 2005                           --------------------------
                                            Name:  Boris Hirmas Said
                                            Title: Legal Representative






                                Index of Exhibits

  Exhibit No.                       Description
  -----------                       -----------

       1            Joint Filing Agreement by and among Tres Mares S.A., Boris
                    Hirmas Said, Maria Pia Hirmas Said, Paola Hirmas Said and
                    Emilia Said de Hirmas.+

       2            Power of Attorney by Tres Mares S.A., Maria Pia Hirmas Said,
                    Paola Hirmas Said and Emilia Said de Hirmas.
---------------------------------------
                    + Incorporated by reference to the Schedule 13G for the
                    Reporting Persons, File No. 005-50478, filed on March 5,
                    2003.
                                                                       Exhibit 1



                                POWER OF ATTORNEY

         Tres Mares S.A., a sociedad anonima organized under the laws of the
Republic of Chile, Maria Pia Hirmas Said, Paola Hirmas Said and Emilia Said de
Hirmas (together the "Hirmas Group") each hereby appoint Boris Hirmas Said (the
"Attorney-in-Fact") as legal representative to execute for and on behalf of the
Hirmas Group, all Schedules 13G under the Securities Exchange Act of 1934, as
amended, and any and all amendments thereto, and to file the same, with all
exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange Commission and relevant stock exchanges (individually,
each a "Filing").

         The undersigned acknowledges that the Attorney-in-Fact, in serving in
such capacity at the request of the undersigned, is not assuming any of the
undersigned's responsibilities to comply with Section 13 of the Securities
Exchange Act of 1934.

         The powers hereby conferred upon the Attorney-in-Fact shall continue in
force until notice of the revocation of this Power of Attorney has been received
by the Attorney-in-Fact.

         IN WITNESS WHEREOF, the undersigned has hereunto subscribed this Power
of Attorney this 11th day of February 2005.

                            [Signature pages follow]





                                           TRES MARES S.A.

February 11, 2005                          By: /s/ BORIS HIRMAS SAID
                                               ----------------------------
                                                    Name:   Boris Hirmas Said
                                                    Title:  Legal Representative


                                           By: /s/ MARIA HIRMAS SAID
                                               ----------------------------
February 11, 2005                                   Maria Pia Hirmas Said


                                           By: /s/ PAOLA HIRMAS SAID
                                               ----------------------------
February 11, 2005                                  Paola Hirmas Said


                                           By: /s/ EMILIA SAID DE HIRMAS
                                               ----------------------------
February 11, 2005                                   Emilia Said de Hirmas