Utah Code § 31A-2-105

Before entering upon the duties of the commissioner's office, the commissioner shall take, subscribe, and file the constitutional oath. If the commissioner takes action in the commissioner's office before complying with this section, in good faith and without knowledge of this requirement, and the validity of the commissioner's action is then challenged, that person may take the oath after the action and the oath shall be given retroactive effect to the date on which the commissioner began the commissioner's duties.