President Joe Biden reassumed his presidential duties after going under anaesthesia for a routine colonoscopy, during which time, Vice President Kamala Harris served as acting president of the United States.“As was the case when President George W Bush had the same procedure in 2002 and 2007, and following the process set out in the Constitution, President Biden will transfer power to the Vice President for the brief period of time when he is under anaesthesia,” White House Press Secretary Jen Psaki said in a statement. “The Vice President will work from her office in the West Wing during this.