EXHIBIT 99.1

Change of Control Definition, As Amended,
in Section 3.1(e) of the 2000 Long-Term Incentive Plan of Emdeon Corporation

     “Change of Control” means and includes the occurrence of any one of the following events:

     (i) individuals who, at the Effective Date, constitute the Board (the “Incumbent Directors”) cease for any reason to constitute at least a majority of the Board, provided that any person becoming a director after the Effective Date and whose election or nomination for election was approved by a vote of at least a majority of the Incumbent Directors then on the Board (either by a specific vote or by approval of the proxy statement of the Corporation in which such person is named as a nominee for director, without written objection to such nomination) shall be an Incumbent Director; provided, however, that no individual initially elected or nominated as a director of the Corporation as a result of an actual or threatened election contest (as described in Rule 14a-11 under the 1934 Act (“Election Contest”) or other actual or threatened solicitation of proxies or consents by or on behalf of any “person” (as such term is defined in Section 3(a)(9) of the 1934 Act and as used in Section 13(d)(3) and 14(d)(2) of the 1934 Act) other than the Board (“Proxy Contest”), including by reason of any agreement intended to avoid or settle any Election Contest or Proxy Contest, shall be deemed an Incumbent Director;

     (ii) any person becomes a “beneficial owner” (as defined in Rule 13d-3 under the 1934 Act), directly or indirectly, of securities of the Corporation representing 25% or more of the combined voting power of the Corporation’s then outstanding securities eligible to vote for the election of the Board (the “Company Voting Securities”) and, in connection therewith, the Committee has determined, in its sole discretion, that a change in control of the Corporation has occurred or is reasonably expected to occur, taking into consideration all relevant facts and circumstances, including, but not limited to, any changes in the membership or structure of the Board; provided, however, that the event described in this paragraph (ii) shall not be deemed to be a Change in Control of the Corporation by virtue of any of the following acquisitions: (A) any acquisition by a person who is on the Effective Date the beneficial owner of 25% or more of the outstanding Company Voting Securities, (B) an acquisition by the Corporation which reduces the number of Company Voting Securities outstanding and thereby results in any person acquiring beneficial ownership of more than 25% of the outstanding Company Voting Securities; provided, that if after such acquisition by the Corporation such person becomes the beneficial owner of additional Company Voting Securities that increases the percentage of outstanding Company Voting Securities beneficially owned by such person, a Change in Control of the Corporation shall then occur, (C) an acquisition by any employee benefit plan (or related trust) sponsored or maintained by the Corporation or any Parent or Subsidiary, (D) an acquisition by an underwriter temporarily holding securities pursuant to an offering of such securities, or (E) an acquisition pursuant to a Non-Qualifying Transaction (as defined in paragraph (iii)); or

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     (iii) the consummation of a reorganization, merger, consolidation, statutory share exchange or similar form of corporate transaction involving the Corporation that requires the approval of the Corporation’s stockholders, whether for such transaction or the issuance of securities in the transaction (a “Reorganization”), or the sale or other disposition of all or substantially all of the Corporation’s assets to an entity that is not an affiliate of the Corporation (a “Sale”), unless immediately following such Reorganization or Sale: (A) more than 50% of the total voting power of (x) the corporation resulting from such Reorganization or the corporation which has acquired all or substantially all of the assets of the Corporation (in either case, the “Surviving Corporation”), or (y) if applicable, the ultimate parent corporation that directly or indirectly has beneficial ownership of 100% of the voting securities eligible to elect directors of the Surviving Corporation (the “Parent Corporation”), is represented by the Corporation Voting Securities that were outstanding immediately prior to such Reorganization or Sale (or, if applicable, is represented by shares into which such Company Voting Securities were converted pursuant to such Reorganization or Sale), and such voting power among the holders thereof is in substantially the same proportion as the voting power of such Company Voting Securities among the holders thereof immediately prior to the Reorganization or Sale, (B) no person (other than (x) the Corporation, (y) any employee benefit plan (or related trust) sponsored or maintained by the Surviving Corporation or the Parent Corporation, or (z) a person who immediately prior to the Reorganization or Sale was the beneficial owner of 25% or more of the outstanding Company Voting Securities) is the beneficial owner, directly or indirectly, of 25% or more of the total voting power of the outstanding voting securities eligible to elect directors of the Parent Corporation (or, if there is no Parent Corporation, the Surviving Corporation), and (C) at least a majority of the members of the board of directors of the Parent Corporation (or, if there is no Parent Corporation, the Surviving Corporation) following the consummation of the Reorganization or Sale were Incumbent Directors at the time of the Board’s approval of the execution of the initial agreement providing for such Reorganization or Sale (any Reorganization or Sale which satisfies all of the criteria specified in (A), (B) and (C) above shall be deemed to be a “Non-Qualifying Transaction”).

Notwithstanding anything herein to the contrary, neither the consummation of the merger contemplated by that certain Agreement and Plan of Merger dated as of February 13, 2000 between the Corporation and Medical Manager Corporation, as amended, nor the consummation of the merger contemplated by that certain Agreement and Plan of Merger dated as of February 13, 2000 among the Corporation, Avicenna Systems Corporation and CareInsite, Inc., as amended, shall be deemed to be a “Change of Control” for purposes of this Section 3.1(e).

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