Mo. Rev. Stat. § 473.560

If any executor or administrator fails to appear and file settlement on the day for which his settlement is docketed, the court shall continue the settlement to some future day and issue a citation to the executor or administrator requiring him to file settlement on the day to which the settlement is continued or show good cause, if any he has, why his settlement has not been filed and why his letters should not be revoked. The citation shall be served in the manner prescribed by the court in accordance with section 472.100.