Constitution of the Commonwealth of Pennsylvania Art. IV, § 12. Power to convene and adjourn the General Assembly

He may, on extraordinary occasions, convene the General Assembly, and in case of disagreement between the two Houses, with respect to the time of adjournment, adjourn them to such time as he shall think proper, not exceeding four months.  He shall have power to convene the Senate in extraordinary session by proclamation for the transaction of Executive business.