Mo. Rev. Stat. § 510.330: Granting of new trial.

A new trial may be granted for any of the reasons for which new trials have heretofore been granted. A new trial may be granted to all or any of the parties and on all or part of the issues after trial by jury, court or referee. On a motion for a new trial in an action tried without a jury, the court may open the judgment if one has been entered, take additional testimony, amend findings of fact or make new findings, and direct the entry of a new judgment. Only one new trial shall be allowed on the ground that the verdict is against the weight of the evidence. Every order allowing a new trial shall specify of record the ground or grounds on which said new trial is granted.