I don't know, it sounds like he customarily offers his resignation letters ahead of the each new president's inauguration but Trump accepted it. It does not take effective until 12:01 when Trump is president.
Since Schwartz, 65, was appointed to head the guard in 2008 by President George W. Bush, he offered resignation letters ahead of the 2009 and 2013 inaugurations of President Barack Obama, but those were not accepted, Major Byron Coward, a guard spokesman.
It is unclear who accepted Schwartz’s resignation, which was tendered in December, Coward said. Trump’s transition team has not answered.
Schwartz isn’t the only person who must leave his post as soon as Trump is sworn in as the United States’ 45th commander-in-chief. The president-elect’s transition team issued a blanket edict just before Christmas requiring that all politically appointed ambassadors leave their posts by January 20 “without exceptions,” the New York Times reported.
While the transfer of power between Obama and Trump takes place, Schwartz will transfer command of the DC Guard and the JTF-DC to Brigadier General William Walker, who currently serves as both the commander of the joint task force and the guard’s land component commander. He has been trained to take over.