"I can tell you there's nothing planned at this time for it, but the president has talked about potentially meeting with President Xi and we'll see what progress we make next week," Mnuchin said. "I can tell you one thing about this president. Wherever he is he calls me, so we're not worried about where he is at the end of the month."
The vice president and either a majority of Cabinet members or members "of such other body as Congress may by law provide" need to communicate that wish in writing to the Senate president pro tempore and the Speaker of the House in order for the sitting vice president to become the acting president. However, if the president resists and deems himself capable of fulfilling his duties, the matter heads to Congress: A two-thirds vote in both the House and Senate within 21 days means the vice president remains the acting president; a lesser vote returns the powers to the president.