And, yes, if a discount is released after you have booked you can call back and have the code added to your existing reservation. If they run out of discounted rooms at your booked resort, you can have them check for availability at another resort and have the discount code added. You do not have to cancel your reservation and your reservation number stays the same. But, really, if you call immediately when a new discount code is released, you should just be able to add the code to your existing reservation with no issues.