Tenn. Code Ann. § 4-3-505

The commissioner is authorized to appoint such deputy and assistant commissioners as may be necessary to discharge the powers and duties of the department. In the event of absence or incapacity of the commissioner or in the event of a vacancy in the office of the commissioner, an appropriate person designated by the governor may be authorized, in accordance with § 4-4-115, to exercise any and all of the powers of the commissioner until such time as the duly appointed commissioner can fulfill such commissioner's responsibilities.