Mo. Rev. Stat. § 508.012
Current with changes from the 2023 Legislative Session
At any time prior to the commencement of a trial, if a plaintiff or defendant, including a third-party plaintiff or defendant, is either added to, removed, or severed from a petition filed in any court in the state of Missouri which would have, if originally added to, removed, or severed from the initial petition, altered the determination of venue under section 508.010, then the judge shall upon application of any party transfer the case to a proper forum.
§ 508.012, RSMo