When the post of commander-in-chief was converted into the post of Chief of Army Staff?

When the post of commander-in-chief was converted into the post of Chief of Army Staff?

کمانڈر انچیف کا عہدہ چیف آف آرمی سٹاف کے عہدے میں کب تبدیل ہوا؟
Explanation

General Tikka Khan was the first chief of army staff from March 1972 until retiring on March 1976

Changed: 20 March 1972

From 1947 to 1972: The Commander-in-Chief of the Pakistan Army (reporting name: C-in-C) was normally the highest-ranking officer in the Pakistan Army.