<PAGE>

                                                                   Exhibit 10.22

                                AMENDMENT TO THE
                             DEAN WITTER START PLAN
                             ----------------------

     WHEREAS, Dean Witter Reynolds Inc. ("DWR"), a Delaware corporation,
maintains the Dean Witter START Plan (the "START Plan");

     WHEREAS, DWR desires that the START Plan be amended as set forth herein;

     NOW, THEREFORE, the START Plan is hereby amended as follows:

1.     Effective January 1, 2000, Section 11(c) of the START Plan shall be
   amended by adding two new sentences immediately following the third sentence
   thereof to read as follows:

     "Effective January 1, 2000, if a Participant whose vested Accounts exceed
     the amount described in Section 411(a)(11) of the Code on the date the
     distribution commences does not consent to the distribution of the
     Participant's Plan Benefit under Section 11(b), then payment of the
     Participant's Plan Benefit shall, subject to Section 13(a), be deferred to
     such date as the Participant shall elect.  Notwithstanding the foregoing,
     effective January 1, 2000, if the Participant's vested Accounts do not
     exceed $5,000 as of January 1 (or such other date(s) as the Plan
     Administrator shall designate from time to time), then the deferral of the
     Participant's Plan Benefit shall end, and distribution of the Participant's
     Plan Benefit shall be made approximately 90 days thereafter, provided,
     however, that at the time of distribution the Participant's vested Accounts
     do not, in fact, exceed $5,000."

2.       Effective January 1, 1999, Morgan Stanley International Incorporated
   ("MSII") shall be a Participating Company, as defined in the START Plan, with
   respect to MSII employees primarily servicing business units or cost centers
   of otherwise Participating Companies;

3.       Effective as of January 1, 1999, the first sentence of Section
   4(b)(i)(3) of the START Plan is hereby amended by inserting the words ",
   determined with regard to the Participant's Earnings while an Eligible
   Employee" within the parenthetical and immediately following the words "up to
   6% of Earnings."
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4.       Effective July 1, 1999, the fifth sentence of Section 6(d) of the START
   Plan is amended by adding the words ", is fully (100%) vested" after the
   words "who has attained age 55" and after the words "who has attained age
   60."

       IN WITNESS WHEREOF, the undersigned had hereunder set his hand as of the
22nd day of December, 1999.

                                    DEAN WITTER REYNOLDS INC.

                                    By: /s/ Michael T Cunningham
                                        ------------------------
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                                                                   Exhibit 10.22


                                AMENDMENT TO THE
                             DEAN WITTER START PLAN
                             ----------------------

          WHEREAS, pursuant to a Stock Purchase Agreement between SPS
Transaction Services, Inc. ("SPS") and Associates First Capital Corporation
("Associates"), SPS has sold substantially all of its assets to Associates and
all of the common stock of SPS held by the Dean Witter START Plan (Saving Today
Affords Retirement Tomorrow) (the "Plan") has been converted into cash; and

          WHEREAS, the Compensation Committee of Dean Witter Reynolds Inc. (the
"Company") has determined that, as a result of the closing of the transaction
between SPS and Associates, it is necessary and appropriate to amend the Plan as
hereinafter set forth and has authorized an officer of the Company to execute
this amendment.

          NOW, THEREFORE, BE IT RESOLVED:

          1.  Section 3(f) of the Plan is amended in its entirety to read as
follows:

          Transferred Employees.  If a Participant transfers employment to SPS
          ---------------------
     Transaction Services, Inc. (or any of its subsidiaries) ("SPS") before
     October 15, 1998 or Nations-Securities, A Dean Witter/Nations Bank Company
     ("Nations"), such transferred Participant's Period of Service shall include
     service with SPS before October 15, 1998 or Nations but not more than the
     lesser of such transferred Participant's service with SPS before October
     15, 1998 or Nations or the service necessary for such transferred
     Participant to fully vest in the Matching Contribution Account, such post-
     transfer service to be determined in accordance with this Section 3.

          2.  Section 3(g) of the Plan is amended in its entirety to read as
follows:

          Service with SPS.  In the case of any individual who was an employee
          ----------------
     of SPS and who either transferred employment to a member of the Affiliated
     Group before October 15, 1998 or severed employment with SPS before October
     15, 1998 and is hired as an Employee by a member of the Affiliated Group
     within 12 months of such severance, such Employee's Service used to
     determine a Year of Service under this Section 3 shall include service with
     SPS before October 15, 1998 determined by applying the rules set forth in
     this Section 3 to such Employee's
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     employment by SPS as if such employment was employment by a member of the
     Affiliated Group.

          3.  Section 6(c) of the Plan is amended by inserting the following new
sentence at the end thereof:

     Notwithstanding any provision of the Plan to the contrary, a Participant
     shall not be permitted to make a Fund Balance Transfer into the SPS Stock
     Fund on or after October 15, 1998.

          4.  Section 7(b) of the Plan is amended by inserting the following new
sentence at the end thereof:

     Notwithstanding any provision of the Plan to the contrary, any amounts that
     are attributable to employer contributions and that are held in the SPS
     Stock Fund on October 15, 1998 shall be transferred to the Morgan Stanley
     Dean Witter Stock Fund as soon as practicable after such date.

          5.  Section 7(c)(v) of the Plan is amended by inserting the following
new sentence at the end thereof:

     Notwithstanding any provision of the Plan to the contrary, as soon as
     practicable after the SPS Stock Conversion Date, the assets of the SPS
     Stock Fund (other than those attributable to employer contributions) shall
     be invested in a U.S. Government money market Investment Fund available
     under the Plan or in such other similar Investment Fund as the Trustee
     deems suitable, and thereafter the SPS Stock Fund shall terminate and cease
     to be an Investment Fund under the Plan.

          6.  Section 9(a) of the Plan is amended by inserting the following new
sentence at the end thereof:

     Notwithstanding any provision of the Plan to the contrary, an Employee
     shall not be permitted to make such a contribution on or after October 15,
     1998 in the form of Stock received from a plan maintained by SPS or a note
     evidencing a participant loan under the SPS Transaction Services, Inc.
     START Plan.

          7.  The first sentence of Section 12(h)(ix) of the Plan is amended by
inserting the phrase "before October 15, 1998" at the end thereof.
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          8.  The first sentence of Section 12(h)(x) of the Plan is amended by
inserting the phrase "before October 15, 1998" at the end thereof.

          9.  Section 21 of the Plan is amended by inserting the following new
definition immediately after the definition of "SPS Stock":

          "SPS Stock Conversion Date" means the date upon which SPS Stock is
           -------------------------
     converted into cash in accordance with the Stock Purchase Agreement between
     SPS and Associates First Capital Corporation.

          10.  The Plan is further amended by inserting the following new
Supplement E immediately after Supplement D:

                                  SUPPLEMENT E

                                  SALE OF SPS

          Pursuant to a Stock Purchase Agreement between SPS and Associates
     First Capital Corporation ("Associates"), SPS has sold substantially all of
     the stock of its subsidiaries to Associates, and all of the SPS Stock held
     by the Plan was converted into cash.  Accordingly, except where the context
     clearly requires otherwise, all of the references in the Plan to SPS, the
     SPS START Plan, SPS Stock and the SPS Stock Fund shall be deemed to be
     deleted effective as of the SPS Stock Conversion Date.  Following such sale
     there were no employees of SPS, the SPS START Plan was transferred to
     Associates, and the SPS Stock Fund was terminated.

          11.  The foregoing amendments to the Plan shall be effective as of
October 15, 1998.


       IN WITNESS WHEREOF, the undersigned had hereunder set his hand as of the
22nd day of December, 1999.


                                    DEAN WITTER REYNOLDS INC.

                                    By: /s/ Michael T Cunningham
                                       -------------------------