Inside of 31 days the wait list is emptied. If you still want to try for a reservation, you can simply ask to be put back on the list- but they will not automatically do so. The list again dissolves at 7 days- but again, you can ask to be put back on the list.
I would suggest calling regularly once inside of 30 days, if you still are serious about getting a reservation. Cancellations do occur all the time- even within 30 days, but most members will try to cancel before then to avoid the "holding account".
Good Luck!