So on January 19th, Bush announces he will resign the Presidency effective 10 am EST tomorrow and then Dick Cheney announces he will resign the Vice Presidency effective 9:59 am EST tomorrow.
Nancy Pelosi is then sworn in for the interim 2 hours until the new president is sworn in at noon EST.
By Constitutonal law, she must resign her seat in the House of Representatives in order to ascend to the Presidency.
At 12:01 Nancy is then no longer President, no longer Speaker, no longer employed.