§ 1531. Transfers of functions and activities
(a)
The balance of an appropriation available and necessary to finance or discharge a function or activity transferred or assigned under law within an executive agency or from one executive agency to another may be transferred to and used—
(b)
The head of the executive agency determines the amount that, with the approval of the President, is necessary to be transferred when the transfer or assignment of the function or activity is within the agency. The President determines the amount necessary to be transferred when the transfer or assignment of the function or activity is from one executive agency to another.