Pakistan became a republic under the Constitution of 1956 and the Monarch and Governor-General were replaced by a ceremonial President.
The Governor-General was appointed for an indefinite term, serving at the pleasure of the monarch.
After the passage of the Statute of Westminster 1931, the Governor-General was appointed solely on the advice of the Cabinet of Pakistan without the involvement of the British government.
In the event of a vacancy the Chief Justice served as Officer Administering the Government.
In the event of a vacancy the Chairman of the Senate served as Acting President.