If a vacancy occurs in the office of mayor more than one hundred eighty days before the time of holding the next succeeding regular city election, the board of canvassers shall call a special election for the purpose of filling such vacancy for the remainder of the term, such special election to be held not less than thirty nor more than fifty days after the date of the occurrence of such vacancy. If any such vacancy occurs one hundred eighty days, or less, before the time of holding the next succeeding regular city election, the board of canvassers shall call a special election for said purpose, to be held not less than thirty nor more than fifty days after the date of the occurrence of such vacancy, on demand therefor in writing signed by at least one-third of all the members of the council, and filed with the board of canvassers and the city clerk at least sixty days prior to the time of holding the next succeeding regular city election. In the event that any state election, regular or special, or any city election for any other purpose shall be held within the said period in which an election is required to be held hereunder, the board of canvassers, may in its discretion order any special election required by the provisions of this section to be held at the same time as such other city or state election. Until the vacancy is filled or in case of the mayor's temporary disability or absence from the city, the president of the council shall act as mayor; and if the president of the council shall resign or be unable to act, then the council shall elect by a majority of its members one of its members to serve as acting mayor.
A vacancy in a appointive office for a term shall be filled by appointment for the balance of the unexpired term. Such an appointment shall be made in the same manner as an original appointment.