It was a standing order
I get that, but Trump should be wise enough (not just because by the end of his first term he understood the swamp was out to get him, but also because he was the subject of thousands of lawsuits, multiple divorces, perpetual IRS audits, and hundreds of new York city real estate contracts that if it isn't written down, there is no proof that it happened. There should be no difficulty finding the location of a memo or document which references it or specifies that standing order.