If there has not been a schedule change on your original ticket, then the $100 change fee applies. If one occurs later, you can get a full refund for free.

If you don't have the second ticket yet, I can't see how you can be waitlisted. I guess that means the first ticket is waitlisted on your preferred route. This could be a problem. If the first ticket clears the new routing, you wouldn't be able to book another ticket since you already took the award seat.