53 Pa. Stat. § 13110
The proposed new charter or amendments shall be submitted to the electors for approval or disapproval by the use of the ballot questions, framed as aforesaid, at a special election occurring more than forty-five days after the proposed new charter is filed with the city council of the city or the final enactment of an ordinance by the city council providing for the submission of amendments, as aforesaid. In the case of a proposed new charter, such special election shall be held on such day as shall be fixed and designated by the charter commission, which day may be the day for holding any primary or regular November election or a day other than a day for holding any election in the city. In the case of proposed amendments to a charter, such special election shall be held on the day of any primary or regular November election as shall be fixed and designated by the city council in the ordinance enacted under the provisions of section six of this act. Whenever a proposed new charter or amendments to the charter shall propose any change in the manner of selection of elected city officers, such proposal shall be submitted by a separate ballot question.
53 P.S. § 13110