Mo. Rev. Stat. § 513.375: Any person owing defendant may pay officer, how.

After the issuing of an execution, any person indebted to the defendant therein may pay to the sheriff or other officer charged with the collection thereof, the amount of the debt owing by such person to such defendant, or so much thereof as shall be necessary to satisfy the execution and costs, and the officer's receipts shall be a sufficient discharge for the amount paid.