Originally Posted by
findark
I'm sure if you ask they will reroute you IAD-SFO/LAX-SYD or change days to the nearest DCA-IAH-SYD. They can't reroute you DCA-LAX-SYD because UA does not fly DCA-LAX.
They do fly DCA-SFO though, so DCA-SFO-SYD would be another option.