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                                                             EXHIBIT         4.1

                          AMENDMENT TO RIGHTS AGREEMENT

         Amendment dated as of March 15, 2004, to the Rights Agreement, dated as
of September 12, 1997 (the "Rights Agreement"), between Mission Resources
Corporation, a Delaware corporation formerly known as Bellwether Exploration
Company (the "Company"), and American Stock Transfer & Trust Company, a New York
corporation, as Rights Agent (the "Rights Agent"), as amended to date.

         WHEREAS, the Company and the Rights Agent entered into the Rights
Agreement specifying the terms of the Rights (as defined therein);

         WHEREAS, the Company desires to amend the Rights Agreement in
accordance with Section 27 of the Rights Agreement;

         WHEREAS, the Company proposes to enter into a Purchase and Sale
Agreement dated as of March 15, 2004 (the "Purchase Agreement"), by and between
Harbert Distressed Investment Master Fund, Ltd. ("Harbert") and the Company;

         WHEREAS, the Board of Directors of the Company has determined it
advisable and in the best interest of its stockholders to amend the Rights
Agreement to enable the Company to enter into the Purchase Agreement and
consummate the transactions contemplated thereby without causing Harbert or any
of their respective affiliates or associates to become an "Acquiring Person" (as
defined in the Rights Agreement).

         NOW, THEREFORE, in consideration of the premises and mutual agreements
set forth herein and in the Rights Agreement, the parties hereby agree as
follows:

         Section 1. Definitions. Capitalized terms used and not otherwise
defined herein shall have the meaning assigned to such terms in the Rights
Agreement.

         Section 2. Amendments to Rights Agreement. The Rights Agreement is
hereby amended as set forth in this Section 2.

         (a) The definition of "Acquiring Person" in Section 1 of the Rights
Agreement is amended to add the following sentence at the end thereof:

         "Notwithstanding anything in this Agreement to the contrary, neither of
         Harbert or any Affiliate or Associate of any of them shall be deemed to
         be an Acquiring Person, either individually or collectively, solely by
         virtue of (i) the execution and delivery of the Harbert Purchase
         Agreement, or (ii) the issuance and delivery of shares of Common Stock
         in accordance with Article 2 of the Harbert Purchase Agreement."

         (b) The definition of "Distribution Date" in Section 1 of the Rights
Agreement is amended to add the following sentence at the end thereof:

         "Notwithstanding anything in this Agreement to the contrary, a
         Distribution Date shall not be deemed to have occurred solely as the
         result of (i) the execution and

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         delivery of the Harbert Purchase Agreement, or (ii) the issuance and
         delivery of shares of Common Stock in accordance with Article 2 of the
         Harbert Purchase Agreement."

         (c) The definition of "Stock Acquisition Date" in Section 1 of the
Rights Agreement is amended to add the following sentence at the end thereof:

         "Notwithstanding anything in this Agreement to the contrary, a Stock
         Acquisition Date shall not be deemed to have occurred solely as the
         result of (i) the execution and delivery of the Harbert Purchase
         Agreement, or (ii) the issuance and delivery of shares of Common Stock
         in accordance with Article 2 of the Harbert Purchase Agreement."

         (e) The following definitions shall be added to Section 1 of the Rights
Agreement:

         "'Harbert' shall mean Harbert Distressed Investment Master Fund, Ltd."

         "'Harbert Purchase Agreement' shall mean the Purchase and Sale
         Agreement dated as of March 15, 2004, by and between Harbert and the
         Company."

         Section 3. Miscellaneous.

         (a) The term "Agreement" as used in the Rights Agreement shall be
deemed to refer to the Rights Agreement as amended to date and as amended
hereby.

         (b) This Amendment shall be effective as of the date first above
written, and, except as set forth herein, the Rights Agreement shall remain in
full force and effect and shall be otherwise unaffected hereby.

         (c) This Amendment may be executed in two or more counterparts, each of
which shall be deemed to be an original, but all for which together shall
constitute one and the same instrument.

         (d) This Amendment shall be deemed to be a contract made under the laws
of the State of Delaware and for all purposes shall be governed by and construed
in accordance with the laws of such State applicable to contracts to be made and
performed entirely within such State.

                            [SIGNATURE PAGE FOLLOWS]

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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and attested, all as of the day and year first above written.

Attest:                                     MISSION RESOURCES CORPORATION

By: /s/ Ann Kaesermann                      By: /s/ Robert L. Cavnar
   ----------------------------------          --------------------------------
Name: Ann Kaesermann                        Name: Robert L. Cavnar
      ------------------------------             ------------------------------
Title:VP Accounting & Investor Relations    Title: Chairman, President and CEO
      ----------------------------------           ----------------------------

Attest:                                     AMERICAN STOCK TRANSFER &
                                                   TRUST COMPANY

By: /s/ Susan Silber                        By: /s/ Paula Caroppoli
    ------------------------------------       --------------------------------
Name: Susan Silber                          Name: Paula Caroppoli
      ----------------------------------         ------------------------------
Title:Assistant Secretary                   Title: Vice President
      ----------------------------------          -----------------------------

                                       3exv4w1

 

EXHIBIT 4.1

FIRST AMENDMENT TO RIGHTS AGREEMENT

     THIS FIRST AMENDMENT TO RIGHTS AGREEMENT (this “Amendment”), dated as of
March 10, 2004, is between American Management Systems, Incorporated, a
Delaware corporation (the “Company”), and Mellon Investor Services LLC
(formerly known as ChaseMellon Shareholder Services L.L.C.), a New Jersey
limited liability company, as rights agent (the “Rights Agent”).

     WHEREAS, the Company and the Rights Agent are parties to a Rights
Agreement, dated as of July 31, 1998 (the “Rights Agreement”); and

     WHEREAS, pursuant to Section 27 of the Rights Agreement, the Company and
the Rights Agent desire to amend the Rights Agreement as set forth below;

     NOW, THEREFORE, the Rights Agreement is hereby amended as follows:

     1. Amendment
of Section 1.

     Section 1 of the Rights Agreement is amended by adding thereto subsections
(gg) and (hh) which shall read as follows:

“(gg) ‘Agreement and Plan of Merger’ shall mean the
Agreement and Plan of Merger, dated as of March 10,
2004, by and among CGI Group Inc., a Québec
corporation (the “Parent”), CGI Virginia
Corporation, a Delaware corporation and wholly-owned
subsidiary of the Parent (the “Merger Sub”), and the
Company, as the same may be amended from time to
time.”

“(hh) ‘Stockholders Agreements’ shall mean the
Stockholder Tender and Voting Agreements, dated as
of March 10, 2004, among Parent, Merger Sub and each
of the stockholders party thereto.”

     2. Amendment
of Section 7.

     Paragraph (a) of Section 7 of the Rights Agreement is amended by deleting
the word “or” immediately preceding clause (iii) thereof and by adding the
following new phrase immediately following clause (iii) thereof: “or (iv)
immediately prior to the acceptance for payment of, and payment for, the Shares
pursuant to the Offer (as such terms are defined in the Agreement and Plan of
Merger).”

 

 

     3. Addition
of New Section 35.

                      The Rights Agreement is amended by adding a Section 35 thereof which shall
read as follows:

“Section 35.
Exception For Agreement and Plan of
Merger. Notwithstanding any provision of this
Agreement to the contrary, neither a Distribution
Date, a Flip-In Event, nor a Stock Acquisition Date
shall be deemed to have occurred, none of the Parent
or the Merger Sub or any of their Affiliates or
Associates shall be deemed to have become an
Acquiring Person, and no holder of any Rights shall
be entitled to exercise such Rights under, or be
entitled to any rights pursuant to, any of Sections
3(a), 7(a), 11(a) or 13 of this Agreement, in any
such case by reason of (a) the approval, execution
or delivery of the Agreement and Plan of Merger or
any amendments thereof approved in advance by the
Board of Directors of the Company, (b) the approval,
execution or delivery of the Stockholders Agreements
or any amendments thereof approved in advance by the
Board of Directors of the Company, or (c) the
commencement or, prior to termination of the
Agreement and Plan of Merger, the consummation of
any of the transactions contemplated by the
Agreement and Plan of Merger or the Stockholders
Agreement in accordance with their respective
provisions, including, without limitation, the
making of the Offer, the acceptance of payment for shares of stock by the Merger Sub pursuant to the
Offer and the Merger (as defined in the Agreement
and Plan of Merger).”

     4. Effectiveness.

     This Amendment shall be deemed effective as of the date first written
above as if executed by both parties hereto on such date. Except as amended
hereby, the Rights Agreement shall remain in full force and effect and shall be
otherwise unaffected hereby.

     5. Miscellaneous.

     This Amendment shall be deemed to be a contract made under the laws of the
State of Delaware and for all purposes shall be governed by and construed in
accordance with the laws of such state applicable to contracts to be made and
performed entirely within such state. This Amendment may be executed in any
number of counterparts, each of such counterparts shall for all purposes be
deemed to be an original, and all such counterparts shall together constitute
but one and the same instrument. If any term,
provision, covenant or restriction of this Amendment is held by a court of
competent jurisdiction or other authority to be invalid, illegal, or
unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Amendment shall remain in full force and effect and shall
in no way be affected, impaired or invalidated.

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     IN WITNESS WHEREOF, the parties hereto have caused this Amendment No. 1 to
be duly executed and their respective corporate seals to be hereunto affixed
and attested, all as of the day and year first above written.

ATTEST:

By /s/ David R. Fontaine

                                                                                               

     Name: David R. Fontaine

     Title: Executive Vice

     President, General Counsel and Secretary

ATTEST:

By /s/ Linda Fuhrer

                                                                                               

Name: Linda Fuhrer

Title: Client Service Manager

AMERICAN MANAGEMENT

SYSTEMS, INCORPORATED

By /s/ Alfred T. Mockett

                                                                                               

Name: Alfred T. Mockett

Title: Chairman and Chief Executive Officer

MELLON INVESTOR SERVICES LLC,

as Rights Agent

By /s/ Cynthia Pacolay

                                                                                               

Name: Cynthia Pacolay

Title: Client Services Manager

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