Mo. Rev. Stat. § 512.250: Associate circuit judge or clerk to file transcript with clerk for trial de novo.

When an application for a trial de novo is timely filed, the associate circuit judge or the clerk who has custody of the case papers shall forthwith transmit the case papers in the cause or a transcript thereof to the clerk receiving cases originally filed for hearing and determination before a circuit judge, and the cause shall thereupon be assigned for a trial de novo before a circuit or associate circuit judge in accordance with assignment procedures prescribed by local circuit court rule or as directed by the presiding judge of the circuit.