In case of the temporary absence or inability of any city member of the Board of Supervisors, including the Mayor to serve or perform the duties of his office as a representative on the Eaton County Board of Supervisors, the Mayor shall designate and certify to the Board of Supervisors another city officer or an elector of the city having the qualifications required by this Charter of elective officers to serve in his stead during the period of such temporary absence or inability.