How do Stevie and Susan Carol gain access to Chip Graber's room in Chapter 9?

Stevie and Susan Carol find the list of players' room numbers in Jerry Ventura's room. They realize Chip doesn't have a roommate. Stevie and Susan Carol go down to the front desk to get a copy of the keycard and a replacement card for Jerry Ventura so he doesn't know they have a copy of his room key to access the players' floors.