Earlier quoted context omitted.
They aren't. They are informing the President and the President does it either by EO or asking congress.
neither have happened and virtually all employees of USAID have been put on leave at the orders of the acting deputy administrator. (via CNN) - It is not legal for the president to unilaterally “abolish, move, or consolidate USAID”. He needs to have congressional authorization to do so.
The President hasn't shut down the USAID yet. They just froze it with the intent to abolish it.