Mo. Rev. Stat. § 473.092

At any time during a proceeding commenced pursuant to this chapter, or, after the death of a ward, at any time during a proceeding commenced pursuant to chapter 475, upon petition by any person who could have applied to the court pursuant to section 473.090 or section 473.097, if the court finds the requirements of either section would have been initially met, the court may order the pending matter be completed under section 473.090 or section 473.097 and proceed pursuant to either section as authorized by statute. The court may proceed with or without notice to any interested party.