<PAGE>

                                                                  EXHIBIT 10.7.3

                                 Amendment No. 6
              to CRS Marketing, Services and Development Agreement

This Amendment No. 6 to the CRS Marketing, Services and Development Agreement
(the "Amendment") is entered into as of January 1, 2002 (the "Amendment
Effective Date"), by and between Expedia, Inc. ("EI"), a Washington corporation
with its principal office at 13810 SE Eastgate Way, Suite 400, Bellevue, WA
98005, and Worldspan, L.P., a Delaware limited partnership ("Worldspan"), with
its principal office at 300 Galleria Parkway, NW, Atlanta, Georgia 30339.

                                    Recitals

         Microsoft Corporation ("Microsoft") and Worldspan entered into that
certain CRS Marketing, Services and Development Agreement dated December 15,
1995, as amended by the parties pursuant to that certain Amendment No. 1 dated
January 1, 1997, Amendment No. 2 dated July 1, 1998, Amendment No. 3 dated April
1, 1999, Amendment No. 4 dated July 1, 2001, and Amendment No. 5 dated October
22, 2001 (collectively, the "Agreement").

         Microsoft's rights and obligations under the Agreement have been
assigned to and assumed by EI, which is the successor in interest to Microsoft
for all purposes relating to the Agreement.

         EI and Worldspan now desire to modify the Agreement as set forth
herein.

         Now, Therefore, in consideration of the above recitals, the mutual
undertakings of the parties as contained herein and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties to this Amendment hereby agree as follows:

1.       Definitions
         -----------

         (a)   Terms in capitalized form not defined in this Amendment No. 6
shall have the meanings set forth in the Agreement.

         (b)   Effective as of January 1, 2002, Paragraph F of Schedule 11.1
attached as Appendix 1 to Amendment No. 4 of the Agreement is amended by adding
the following new definitions:

               "Domestic Automated Reissue" means one automated comparison of an
                --------------------------
         old itinerary to a new itinerary and recalculation of the new fare,
         including additional collections, refunds, penalties and administrative
         fees, provided that (i) all segments in the itinerary must be within
         and/or between the United States of America, Puerto Rico and the U.S.
         Virgin Islands, (ii) the itinerary must be on the same carrier, and
         only on carriers that participate in Automated Reissues, (iii)
         electronic ticket itineraries must be issued by Worldspan (IATA code
         1P), (iv) the itinerary must be priced and re-priced in U.S. currency,
         (v) all passengers in the ticket record must have the same itinerary,

[*] The redacted portion, indicated by this symbol, is the subject of a
confidential treatment request and has been filed separately with the Securities
and Exchange Commission.

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         original fare calculation and ticketing date, and (vi) only non-BSP
         types of exchanges are applicable. EI acknowledges and agrees that
         Domestic Automated Reissues may not be used for certain types of
                                         ---
         itineraries as may be established and modified by Worldspan from time
         to time, including but not limited to, the following itineraries: (i) a
         group PNR, (ii) tickets issued using bulk fares or print routines,
         (iii) tickets issued with the fare printed as free, (iv) electronic
         tickets printed to paper, and (v) BSP types of exchanges. EI further
         acknowledges and agrees that each carrier participating in Automated
         Reissues may establish limits for the number of passengers in a PNR
         that qualify for Automated Reissues and that such limits may change
         from time to time.

2.       Domestic Automated Reissues
         ---------------------------

         (a) Effective as of January 1, 2002, CRS Services shall include the
processing of Domestic Automated Reissues. [*] For each Domestic Automated
Reissue processed by EI (or its authorized service provider) through the
Worldspan System, EI shall pay to Worldspan the transaction fee set forth in the
table below:

             -------------------------------------------------------------------
                  Domestic Automated Reissues
                     (per Contract Year)           Transaction Fee
             -------------------------------------------------------------------
                             [*]                         [*]
             -------------------------------------------------------------------
                             [*]                         [*]
             -------------------------------------------------------------------
                             [*]                         [*]
             -------------------------------------------------------------------

         (b) Charges will be calculated monthly and shall be due within thirty
(30) days following the invoice date. Alternatively, Worldspan may offset the
amount owed to it by EI against any amount that Worldspan owes EI under the
Agreement.

         (c) [*]

3.       Confidentiality
         --------------

         This Amendment shall be considered Confidential Information according
to the Agreement.

4.       Continuation of Agreement
         -------------------------

         Except as provided in this Amendment, the Agreement shall continue in
full force and effect.

[*] The redacted portion, indicated by this symbol, is the subject of a
confidential treatment request and has been filed separately with the Securities
and Exchange Commission.

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed
by their duly authorized undersigned representatives as of the date first above
written.

Expedia, Inc.                           Worldspan, L.P.

By:    /s/ David Beitel                By:  /s/ Michael Parks
       -----------------------------        ------------------------------------


Print Name:  David Beitel              Print Name:     Michael Parks
             -----------------------                ----------------------------

Title: Vice President, Product          Title: Senior Vice President and General
       Development                             ---------------------------------
       -----------------------------           Manager - Worldwide Travel
                                               ---------------------------------
                                               Distribution
                                               ---------------------------------


[*] The redacted portion, indicated by this symbol, is the subject of a
confidential treatment request and has been filed separately with the Securities
and Exchange Commission.

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