Mo. Rev. Stat. § 546.090
Upon the trial of any indictment or information the court may at any stage of the proceeding, in furtherance of justice, amend or supply any pleading, writ, process, entry, return or other proceedings; and the court in which the indictment was found, or the information filed, or in which the trial is had, may at any time before final disposition of the cause, either in such court or the court to which the same may have been appealed, and, whether at the same or different term of court, amend or supply any record in accordance with the fact. If the same be pending on appeal at the time any such record is amended or supplied, the part thereof so amended or supplied shall be immediately certified to the appellate court by the clerk of such trial court.
§ 546.090, RSMo