Legal Question in Wills and Trusts in Missouri

Assuming by "appointed" you mean the deceased person is the one nominated in a will, the process is the same as if there was not a nomination in the will (with the added step of averring the death of that nominated person.) The person that wishes to serve files an application for letters testamentary. If, instead, you mean that the person that the Court has already appointed died before the estate closed, the new person files a request to be appointed successor personal representative. If this is at all confusing to you, consult directly with a probate attorney in your area. Rather than this generalized answer to your general question here, they can give you advice specific to the facts of your situation.

Good luck