What is the legal status of a second agreement that modifies both the term and the payment amount of an existing Kitabah contract?

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If parties attempt to change both the term and the consideration of a Kitabah contract, and that modification is deemed invalid, the modification is void, and the original contract remains in effect. This is because the parties only intended to change the terms in a manner that is not legally sound; there is no valid mutual dissolution (faskh) of the original contract itself.