In any city which by action of its legislative authority establishes the position of secretary of police or the position of secretary of fire, neither such position, if filled by a member of the uniform rank by assignment, shall be subject to competitive examination, notwithstanding section 124.44 of the Revised Code. The status within the uniform ranks of such member while so serving in such assignment shall remain unchanged and, notwithstanding the compensation fixed for such position, he shall not acquire any right to promotion other than such rights to promotion which apply to the rank held at the time of assignment.