President Donald Trump and Sen. Bernie Sanders (Chip Somodevilla/Win McNamee/Getty Images)Bernie Sanders, I-Vt., couldn't nail down a plan for what lawmakers should do if President Trump refuses to concede the White House if he loses in November, but said there will be a "number of plans" if that scenario were to take place.During an interview on HBO's "Real Time with Bill Maher" that aired Friday, Maher pressed Sanders on the specific plan that lawmakers have in place in the event Trump refuses to concede, telling the senator, “I still don’t know what the plan is.”"There are things that we have to do now to make sure that Biden wins," Sanders said.