Mo. Rev. Stat. § 475.341: Voidable transactions, exceptions.

1. Except when a public administrator is serving as conservator, a sale, encumbrance, or other transaction involving the management of the conservatorship entered into by the conservator for the conservator's own personal gain or which is otherwise affected by a conflict between the conservator's fiduciary and personal interests is voidable unless the transaction:

(1) Was approved by the court;

(2) Involves a contract entered into or claim acquired by the conservator before the person became or contemplated becoming conservator;

(3) Involves a deposit of estate moneys to a bank operated by the conservator; or

(4) Involves an advance by the conservator of moneys for the protection of the estate.

2. When a public administrator is serving as conservator, the public administrator shall not enter into a transaction for his or her own personal gain.