As opposed to just not showing up for work?
By Act of Congress (Not the US Constitution) the President's letter of resignation goes to the US Secretary of State.
Jawaharlal Nehru was elected as the President of the Indian National Congress in 1939 after the resignation of Subhash Chandra Bose.
He has 48 hours to notify congress.
War Powers Act
When Richard Nixon resigned in 1974, he submitted his resignation to Secretary of State, Henry Kissinger.
War Powers Act
48 hours
the Vice president should submit his resignation to the President
The War Powers Act requires the president to notify Congress within 48 hours of sending troops into a combat area. There are questions whether the Act is constitutional, and this has not been definitively answered by the Supreme Court.
President
President
president