25 Pa. Stat. § 2939
Any vacancy happening or existing after the date of the primary in any party nomination, by reason of the death or withdrawal of any candidate after nomination, or by reason of the death before or on the day of the primary election of a candidate for nomination who had received a plurality of votes of his party electors cast for the office for which he sought nomination, may be filled by a substituted nomination made by such committee as is authorized by the rules of the party to make nominations in the event of vacancies on the party ticket: Provided, however, That no substitute nomination certificate shall nominate any person who has already been nominated by any political party or by any other political body for the same office. Upon the making of any such substituted nomination, in accordance with the party rules, it shall be the duty of the chairman and secretary or secretaries of the party committee making the nomination to file with the Secretary of the Commonwealth in the case of United States Senator, Representative in Congress and all State officers, including judges of courts of records, senators and representatives, and with the proper county board of elections in the case of other offices, a nomination certificate which shall be signed by the chairman and secretary or secretaries of the said committee, and which shall set forth the following:
25 P.S. § 2939