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                                                                   EXHIBIT 10.21


                       AMENDMENT TO EMPLOYMENT AGREEMENT


         THIS AMENDMENT, effective as of the 26th day of June, 1997, by and
between HUGOTON ENERGY CORPORATION, a Kansas corporation (hereinafter referred
to as the "Company") and DAVID M. DRUMMOND (hereinafter referred to as
"Employee").

         WITNESSETH:

         WHEREAS, the Company and Employee have entered into and executed an
Employment Agreement, dated April 17, 1997 (the "Agreement").

         WHEREAS, the Board of Directors of the Company has unanimously voted
to amend the Agreement and Employee has agreed to the amendments proposed by
the Board of Directors.

         WHEREAS, the parties desire, at this time, to amend and modify said
Agreement in the manner herein specified.

         NOW THEREFORE, in consideration of the premises herein contained, the
parties do hereby agree that said Agreement shall be modified and amended as
follows:

         1.      Paragraph 7(d) shall be deleted in its entirety and the
following shall be substituted in lieu thereof:

                 (d)  Termination By Employee for Good Reason.  If a Change of
         Control (as defined hereafter) in the Company has occurred, Employee
         may terminate his employment during the Employment Period for Good
         Reason (defined hereafter) upon thirty (30) days' notice to the
         Company.  Such notice period may begin prior to the date of the Change
         of Control if an agreement is in place that would have the effect of
         causing a Change of Control.  For purposes of this Agreement, the term
         "Good Reason" shall mean the occurrence, without Employee's express
         written consent, of any one or more of the following events:

                 (i)      A change in Employee's duties or a change in the
                 title or offices held by Employee.

                 (ii)     A reduction in Employee's compensation or the failure
                 by the Company to continue to provide prompt payment (or
                 reimbursement to Employee) of all reasonable expenses incurred
                 by Employee in connection with Employee's professional and
                 business activities.


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                 (iii)    A failure by the Company to waive any and all
                 restrictions that might exist on the exercise of any stock
                 options held by Employee under the Company's stock option
                 plans as of the date of a Change of Control.

                 (iv)     The failure of the Company to obtain the assumption
                 of this Agreement, without limitation or reduction, by any
                 successor to the Company.

         In addition to the above, Good Reason shall be deemed to exist if a
         Change of Control in the Company has occurred and Employee agrees to
         stay employed by the Company for a reasonable transition period after
         the Change of Control, not to exceed three (3) months.

         2.      The payment referred to in the last sentence of Paragraph 9(c)
shall be made within ten (10) days following said termination.

         3.      The parties hereto ratify and confirm all other provisions of
the Employment Agreement.

         IN WITNESS WHEREOF, each of the parties has executed this Agreement as
of the day and year first above written.

"COMPANY"                               "EMPLOYEE"

HUGOTON ENERGY CORPORATION              /s/ DAVID M. DRUMMOND
                                        ---------------------------------
                                        David M. Drummond

By: /s/ FLOYD C. WILSON
    ------------------------------
Name: Floyd C. Wilson
      ----------------------------
Title: President
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ATTEST:

/s/ ILLEGIBLE
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