Section 2616 - Procedure on notice claiming excuse(a) Right of buyer to terminate or modify contract.--Where the buyer receives notification of a material or indefinite delay or an allocation justified under section 2615 (relating to excuse by failure of presupposed conditions) he may by written notification to the seller as to any delivery concerned, and where the prospective deficiency substantially impairs the value of the whole contract under the provisions of this division relating to breach of installment contracts (section 2612), then also as to the whole: (1) terminate and thereby discharge any unexecuted portion of the contract; or(2) modify the contract by agreeing to take his available quota in substitution.(b) Time limitation on modification.--If after receipt of such notification from the seller the buyer fails so to modify the contract within a reasonable time not exceeding 30 days the contract lapses with respect to any deliveries affected.(c) Effect of agreement on section.--The provisions of this section may not be negated by agreement except insofar as the seller has assumed a greater obligation under section 2615. 1979, Nov. 1, P.L. 255, No. 86, § 1, effective 1/1/1980.