There isn't any place to check the status of your waitlist, or even to be sure that you are on a waitlist on line! The best we can do is keep checking to see if the waitlist has come through.
It most likely will be another reservation, not just another night added to a reservation. That's the way it shows up for me when I had a night added to my upcoming BCV stay. The reservations will be linked so you won't have to move.