(6) If a former member shall, within one year from date of discontinuance of service, be employed by another city participating in this retirement system he or she shall have the privilege of redepositing and the matching contributions deposited by the city or cities in which he or she was formerly employed shall again be held for the benefit of such member. If such redepositing member possessed a prior service certificate the city employing him or her at time of retirement shall accept the liability evidenced by such certificate. Reinstatement of a prior service certificate shall be effective only upon a showing that normal contributions are on deposit in the retirement fund, to the credit of the member, covering all current service.