25 Pa. Stat. § 2783
Any person who has been nominated by any political party or political body for a special election as herein provided, may withdraw his name from nomination by a request in writing signed by him and acknowledged before an officer qualified and empowered to administer oaths, and filed in the office of the officer or board with whom the nomination certificate or nomination paper was filed within seven (7) days next succeeding the last day for filing nomination certificates or papers. Such withdrawals to be effective must be received at the office of the Secretary of the Commonwealth or county board of elections, as the case may be, not later than five (5) o'clock P.M. on the last day for filing same. No name, so withdrawn, shall be printed on the ballot or ballot labels. No candidate may withdraw any withdrawal notice already received and filed, and thereby reinstate his nomination.
25 P.S. § 2783