AMENDMENT TO PROMISSORY NOTE This Amendment to that certain Promissory Note, dated December 20, 1996, in the principal amount of $2,300,000 (the "Note"), given by Tipperary Corporation, as "Maker" therein, to Slough Parks Incorporated, as "Lender"...Promissory Note • February 17th, 1998 • Tipperary Corp • Crude petroleum & natural gas
