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                                                                   EXHIBIT 10.51
                                                                   5/14/97 TCIVA

                             AMENDMENT TO AGREEMENT

                  This Amendment to Agreement is made as of the 1st day of
March, 1999, and amends the Non-Qualified Stock Option and Stock Appreciation
Rights Agreement, dated as of May 14, 1997 (the "Agreement"), pertaining to
shares of TCI Ventures Group Series A Common Stock ("TCIVA") by and between
Tele-Communications, Inc. a Delaware corporation (the "Company") and the person
to whom such options were granted as provided in the Agreement (the "Grantee").
All terms used in this Amendment shall have the meanings set forth in the
Agreement except where specifically set forth herein.

                  This Amendment is made pursuant to paragraph 15(a) of the
Agreement which permits the Agreement to be amended to add to the agreements of
the Company for the benefit of the Grantee, provided that such amendment shall
not adversely affect the rights of the Grantee with respect to the Award
evidenced by the Agreement. It has been determined by the Committee that this
Amendment does not adversely affect the rights of the Grantee with respect to
the Award evidenced by the Agreement.

                  Pursuant to the Plan, the Compensation Committee of the Board
has determined that, pursuant to paragraph 15a(ii) of the Agreement:

                  1. Paragraph 4 of the Agreement shall be amended by deleting
the last full paragraph therein in its entirety and deleting the last sentence
of Paragraph 4(a) and replacing such sentence with the following language:

                  Notwithstanding the foregoing, all TCIVA Option Shares shall
                  become available for purchase if Grantee's employment with the
                  Company and its Subsidiaries (i) shall terminate by reason of
                  (x) termination by the Company without cause (as defined in
                  Section 11.2(b) of the Plan), (y) termination by Grantee for
                  good reason (as defined herein) or (z) Disability, (ii) shall
                  terminate pursuant to provisions of a written employment
                  agreement, if any, between the Grantee and the Company which
                  expressly permit the Grantee to terminate such employment upon
                  the occurrence of specified events (other than the giving of
                  notice and passage of time), or (iii) if Grantee dies while
                  employed by the Company or a Subsidiary.

                  2. Paragraph 8 of the Agreement shall be amended to read in
its entirety as follows:

                           8. EARLY TERMINATION OF OPTION AND TANDEM SARS.
                  Unless otherwise determined by the Committee in its sole
                  discretion, the TCIVA Option and TCIVA Tandem SARs shall
                  terminate, prior to the expiration of the TCIVA Option Term,
                  at the time specified below:

                           (a) If Grantee's employment with the Company and its
                  Subsidiaries terminates (i) other than (x) by the Company for
                  "cause" (as defined in Section 11.2(b) of the Plan), (y) by
                  the Grantee with "good reason" (as defined herein) or (z) by
                  the Company without cause, 





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                  and (ii) other than (x) by reason of death or Disability, (y)
                  with the written consent of the Company or the applicable
                  Subsidiary or (z) without such consent if such termination is
                  pursuant to provisions of a written employment agreement, if
                  any, between the Grantee and the Company which expressly
                  permit the Grantee to terminate such employment upon the
                  occurrence of specified events (other than the giving of
                  notice and passage of time), then the TCIVA Option and all
                  TCIVA Tandem SARs shall terminate at the Close of Business on
                  the first business day following the expiration of the 90-day
                  period which began on the date of termination of Grantee's
                  employment;

                           (b) If Grantee dies while employed by the Company or
                  a Subsidiary, or prior to the expiration of a period of time
                  following termination of Grantee's employment during which the
                  TCIVA Option and TCIVA Tandem SARs remain exercisable as
                  provided in paragraph (a), the TCIVA Option and all TCIVA
                  Tandem SARs shall terminate at the Close of Business on the
                  first business day following the expiration of the one-year
                  period which began on the date of death;

                           (c) If Grantee's employment with the Company and its
                  Subsidiaries terminates by reason of Disability, then the
                  TCIVA Option and all TCIVA Tandem SARs shall terminate at the
                  Close of Business on the first business day following the
                  expiration of the one-year period which began on the date of
                  termination of Grantee's employment;

                           (d) If Grantee's employment with the Company and its
                  Subsidiaries is terminated by the Company for "cause" (as
                  defined in Section 11.2(b) of the Plan), then the TCIVA Option
                  and all TCIVA Tandem SARs shall terminate immediately upon
                  such termination of Grantee's employment; or

                           (e) If Grantee's employment (i) is terminated by
                  Grantee (x) with "good reason" (as defined herein), (y) with
                  the written consent of the Company or the applicable
                  Subsidiary or (z) pursuant to provisions of a written
                  employment agreement, if any, between the Grantee and the
                  Company which expressly permit the Grantee to terminate such
                  employment upon the occurrence of specified events (other than
                  the giving of notice and passage of time), or (ii) by the
                  Company without "cause" (as defined in Section 11.2(b) of the
                  Plan), then the TCIVA Option Term shall terminate early only
                  as provided for in paragraph 8(b) above or 12(b) below.

                                    In any event in which the TCIVA Option and
                  TCIVA Tandem SARs remain exercisable for a period of time
                  following the date of termination of Grantee's employment as
                  provided above, the TCIVA Option and TCIVA Tandem SARs may be
                  exercised during such period of time only to the extent the
                  same were exercisable as provided in paragraph 4 above on such
                  date of termination of Grantee's employment. A change of
                  employment is not a termination of employment within the
                  meaning of this paragraph 8 provided that, after giving effect
                  to such change, the Grantee continues to be an employee of the
                  Company or any Subsidiary. Notwithstanding any period of time
                  referenced in this paragraph 8 or any other provision of this
                  paragraph that may be construed to the contrary, the TCIVA
                  Option and all TCIVA Tandem SARs shall in any event terminate
                  upon the expiration of the Option Term.





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                                    "Good reason" for purposes of the Agreement
                  shall be deemed to have occurred upon the happening of any of
                  the following:

                           (i) any reduction in Grantee's annual rate of salary;

                           (ii) either (x) a failure of the Company to continue
                  in effect any employee benefit plan in which Grantee was
                  participating or (y) the taking of any action by the Company
                  that would adversely affect Grantee's participation in, or
                  materially reduce Grantee's benefits under, any such employee
                  benefit plan, unless such failure or such taking of any
                  action, adversely affects the senior members of the corporate
                  management of the Company generally;

                           (iii) the assignment to Grantee of duties and
                  responsibilities that are materially more oppressive or
                  onerous than those attendant to Grantee's position immediately
                  after the date hereof; or

                           (iv) the relocation of the office location as
                  assigned to Grantee by the Company to a location more than 20
                  miles from Grantee's then current location without Grantee's
                  consent.

                  All other terms of the Agreement shall remain the same.

                                        TELE-COMMUNICATIONS, INC.



                                        By:
                                           -------------------------------------
                                                 Stephen M. Brett
                                                 Executive Vice President,
                                                 Secretary and General Counsel






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