There is usually a brochure in your resort room with the offer, the extension to call on the room phone, etc. But sometimes a guest will take the brochure with them and it doesn't get replaced so you must ask at the front desk or concierge desk if there is a bounce back offer and if so, you are eligible to call. We did this in March at our resort, there was no brochure but I figured there might be a possible bounce back offer, and there was.
Also you can book the resort for your future stay, but you can make changes to the date, i.e. add a day or start on a different day, etc., and change the resort once you get home and have the bounce back offer in place. There is a phone # on the brochure that you can call from home, it is a separate number from Central Reservations, etc.