Mo. Rev. Stat. § 443.140: Attorney in fact may enter satisfaction.

Any attorney in fact, to whom the money due on any security instrument is paid, shall have power to execute a release, as specified in section 443.060. Such deed of release, duly acknowledged and recorded, shall have the effect to release the security instrument, and bar all actions brought thereon, and revest in the mortgagor, or person who executed the security instrument, or his legal representatives, all title to the property contained in such security instrument.