Most treaty amendments require the approval and signature of all contracting parties to be valid and applicable. While it is rare for an existing treaty to contain a language explicitly stating that the terms of the treaty cannot be changed under any circumstances, it is unlikely that a treaty change will be legally valid or enforceable. In this case, the parties should terminate the existing contract in accordance with its terms and enter into a new legal contract. If the only change you intend to make is to extend the term of the contract beyond its existing end date, see prototype model extension extension NEW 16/2014 Otherwise, the language of the next prototype can be used to start drafting a contract modification: AMENDMENT This modification is made to this contract [contract number] that was previously executed by and between [AGENCY NAME] as “[AGENCY] and TEXAS TECH UNIVERSITY HEALTH SCIENCE CENTER, [Office or school of `division` or department of `Contracting parties who sign and between them mutually agree to amend this earlier agreement as follows: [Clearly defined changes, complements or deletions using the following three introductory words :] Article 1, paragraph 1 is amended [effective day of the month] , year] and: in Article II, paragraph 2, [effective monthday, year], you add that Article V, paragraph 3 [effective monthday, year] is deleted. All other conditions that are not changed by this condition remain fully applicable and effective. [Insert here the corresponding signature blocks for TTUHSC and FOR AGENCY:] ` Experience has shown that after a series of different contract changes, the resulting contract understanding can conflict between different people. Therefore, we recommend keeping the changes to a minimum. Following the conclusion of an agreement, the contracting parties may have entered into a number of revised agreements over a period of time and, instead of concluding a new agreement, they may only have to review the original agreement.