Procedure on notice claiming excuse.

(2) If after receipt of such notification from the seller the buyer fails so to modify the contract within a reasonable time not exceeding thirty days the contract lapses with respect to any deliveries affected. (3) The provisions of this section may not be negated by agreement except (a) insofar as the seller has assumed a greater obligation under the preceding section; or (b) as set forth in a signed writing between merchants. Cited. 202 C. 277.