71 Pa. Stat. § 73
The Governor shall appoint and fix the compensation of such number of deputy heads of administrative departments, except those of the Department of Auditor General and Treasury Department, as the Executive Board shall approve, who shall, in the absence of the head of such department, have the right to exercise all the powers and perform all the duties by law vested in and imposed upon the head of such department, except the power to appoint bureau or division chiefs, or other assistants or employes, and who may, at any time, exercise such of the powers and perform such of the duties of the head of his department as may be prescribed by the head of his department: Provided, however, That any such deputy shall not have the right to exercise any power or perform any duty which the Constitution of the Commonwealth of Pennsylvania requires the head of his department personally to exercise or perform.
Whenever there shall be a vacancy in the office of the head of any department, such deputy as the Governor shall designate in writing shall exercise the powers and perform the duties of the head of the department until the vacancy is filled.
With the approval of the Governor in writing, the head of any department may authorize a named deputy to serve in his stead on any board or commission, except the Board of Pardons of which such department head is a member ex-officio. One of the Deputy Adjutants General shall possess the same qualifications in all respects as are required by law for the Adjutant General of the Department of Military Affairs.
71 P.S. § 73