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                                                                   EXHIBIT 10.1

                         AMENDMENT TO SERVICE AGREEMENT

         Daniel R. Fischel ("Mr. Fischel") entered into a service agreement with
Lexecon Inc. ("Lexecon") and Nextera Enterprises, Inc. ("Nextera") on December
31, 2002 (the "Service Agreement"). The purpose of this Agreement (this
"Agreement") is to amend certain provisions of the Service Agreement.

         The parties agree as follows:

         1.       The first sentence of Section 5(b) of the Service Agreement is
amended and restated to read as follows:

         "During the term of this Agreement, Mr. Fischel shall manage the
Chicago Office in accordance with the shared goal of Mr. Fischel and the Company
to maximize the operating income of the Chicago Office."

         2.       The first paragraph of Section 5(c) is amended and restated to
read as follows:

         "The Group shall maintain a bonus pool for the Chicago Office (the
"Bonus Pool"), calculated annually based on a calendar year. Mr. Fischel shall
have the authority to allocate the Bonus Pool to himself and the other service
providers in the Chicago Office, subject to the review and approval of the
Compensation Committee of the Board of Directors of the Company (the
"Compensation Committee"); provided, however, that the Compensation Committee
shall not prohibit an allocation of the Bonus Pool to Mr. Fischel which is the
same as his 2001 Percentage (as defined below) of the Bonus Pool without Mr.
Fischel's consent. Notwithstanding the foregoing, Mr. Fischel acknowledges that
it may be in the mutual financial benefit of the parties for the Company to hire
one or more additional senior professionals for the Chicago Office in an effort
to increase the operating income of said office and, in said event, it may be
necessary to provide to said senior professional(s) a percentage of the Bonus
Pool and to decrease Mr. Fischel's percentage of the Bonus Pool to reflect such
hiring and the additional operating income anticipated to be generated for the
Chicago Office by such action. Mr. Fischel agrees in any such events to act in
good faith and not to unreasonably withhold his consent to a request by the
Company to reduce Mr. Fischel's Bonus Pool percentage below the 2001 Percentage.
(Any reference in this Agreement to "Mr. Fischel's Percentage" shall mean his
2001 Percentage as modified as provided above.) The "2001 Percentage" shall mean
36%. The Bonus Pool shall equal:"

         3.       Section 5(l) is deleted in its entirety.

         4.       Mr. Fischel acknowledges that the foregoing amendments to his
Service Agreement do not constitute "Good Reason" for Mr. Fischel to terminate
his employment under the Service Agreement.

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         5.       All other provisions of the Service Agreement remain in full
force and effect, and the parties to said Service Agreement retains all of his
or its rights and remains subject to all of his or its obligations thereunder.

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         Whereas, the parties have entered into this Agreement as of April 24,
2003.

                                                   /s/ Daniel R. Fischel
                                                   -----------------------------
                                                   Daniel R. Fischel

                                                   LEXECON INC.

                                                   By: /s/ MICHAEL P. MULDOWNEY
                                                      --------------------------

                                                   NEXTERA ENTERPRISES, INC.

                                                   By: /s/ RICHARD V. SANDLER
                                                      --------------------------


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