Mo. Rev. Stat. § 529.010
Current with changes from the 2023 Legislative Session
Where any writ of mandamus shall be issued out of any court in this state, or by any judge thereof in vacation, directed and delivered to any person who, by law, is required to make return of such writ, such person shall make his return to the first writ of mandamus.
§ 529.010, RSMo
RSMo 1939 § 1696