53 Pa. Stat. § 23454
If for reasons of economy, lack of funds, abolition of position or positions, or for any other reasons it becomes necessary for any city of the second class to reduce the number of employes then, the city shall follow the following procedure:
First. If there are any employes eligible for retirement under the terms of any pension fund, then such reduction in number shall be made by retirement on pension of all the oldest in age and service;
Second. If the number of employes eligible for retirement under the pension fund of said city, if any, is insufficient to effect the reduction in number desired by said city, or if there is no eligible person for retirement, or if no pension fund exists in such city, then the reduction shall be effected by suspending the last employe or employes regardless of title or classification, including probationers, provisional and substitute employes that have been appointed. Such removal shall be accomplished by suspending in numerical order, commencing with the last employe appointed, all recent appointees until such reduction shall have been accomplished. Whenever the number of such employes shall be again increased in numbers, or if any vacancies occur, the employes suspended under the terms of this act shall be reinstated to that former class before any new appointees are appointed in reverse order to their suspensions.
53 P.S. § 23454