Mo. Rev. Stat. § 545.690
If, in any case, the judge shall be incompetent to sit for any of the causes mentioned in section 545.660, the judge of the court shall set the case down for trial on some day of the term and notify and request another circuit judge to try the case. The judge so requested shall appear and hold the court at the time appointed for the trial of the case; and he shall, during the trial of the case, possess all the powers and perform all the duties of the judge at a regular term of the court, and may adjourn the case from day to day, or to some other time, as the exigencies of the case may require, and may grant a change of venue in the case to the circuit court of another county in the same circuit, or to another circuit. When the cause is removed to the circuit court of another county in the same circuit, the judge so requested shall appear and hold the court at the time set for the trial of the case in the circuit court of the county to which the case is removed. If the judge so requested fails to appear and hold the court at the time appointed for the trial of the case, the judge of the court shall reset the case for trial to suit the convenience of the judge so requested to try the case, or may notify and request the judge of some other circuit to appear and try the cause as heretofore provided. Should the judge so requested fail to appear and hold the court at the time appointed for the trial of the case, the judge of the court shall order a change of venue in the case to some other circuit. The order shall be in writing, and the judge shall file the order with the clerk of the court in which the cause is pending.
§ 545.690, RSMo