Mo. Rev. Stat. § 400.2-606: What constitutes acceptance of goods.

(1) Acceptance of goods occurs when the buyer

(a) after a reasonable opportunity to inspect the goods signifies to the seller that the goods are conforming or that he will take or retain them in spite of their nonconformity; or

(b) fails to make an effective rejection (subsection (1) of section 400.2-602), but such acceptance does not occur until the buyer has had a reasonable opportunity to inspect them; or

(c) does any act inconsistent with the seller's ownership; but if such act is wrongful as against the seller it is an acceptance only if ratified by him.

(2) Acceptance of a part of any commercial unit is acceptance of that entire unit.