The governing body may combine, merge, or consolidate by ordinance any of the various offices of city government as it deems necessary and convenient for the administration of the affairs or government of the city. Any consolidation of elected city offices shall go into effect at the end of the term of office of those officers whose offices are consolidated or when a vacancy occurs in one of the offices to be consolidated. An ordinance consolidating offices must be enacted at least thirty (30) days prior to the date of the next municipal primary election.