Mo. Rev. Stat. § 77.706

Whenever the county governing body shall dissolve any city of the third classification, the county governing body shall appoint some competent person to act as trustee for the corporation so dissolved, and such trustee, before entering upon the discharge of his or her duties, shall take and subscribe an oath that he or she will faithfully discharge the duties of his or her office and shall give bond with sufficient security, to be approved by the governing body, to the use of such disincorporated city, conditioned for the faithful discharge of his or her duty.