Mo. Rev. Stat. § 400.2A-514: Waiver of lessee's objections.

(1) In rejecting goods, a lessee's failure to state a particular defect that is ascertainable by reasonable inspection precludes the lessee from relying on the defect to justify rejection or to establish default:

(a) if, stated seasonably, the lessor or the supplier could have cured it (Section 400.2A-513); or

(b) between merchants if the lessor or the supplier after rejection has made a request in writing for a full and final written statement of all defects on which the lessee proposes to rely.

(2) A lessee's failure to reserve rights when paying rent or other consideration against documents precludes recovery of the payment for defects apparent on the face of the documents.