Like the PP said, just call. They are friendly and helpful. I was actually told that I have until 5 days prior to check in to change without a penalty. I've changed dates already, it was NO problem.
That is true for hotel only bookings. Packages are different.
Here is what the website says:
Revision Fees:
Once deposit and/or full payment is received, a $50 revision fee per transaction, plus any applicable services fees or price increases, will be assessed for any changes made to the reservation including, but not limited to, dates, air carrier, hotel, and ground transportation. If your vacation includes airline reservations, air change fees apply, plus a $50 per reservation revision fee and any other fees or price increases imposed by the airline will be charged. Fees are non-refundable. Certain types of airline reservation changes, including name changes, are prohibited based upon restrictions imposed by the carrier.
Cancellation Fee for Bookings:
DAYS PRIOR TO ARRIVAL - PENALTIES
45 days or more - Full refund*
44-6 days - $100 fee per reservation, plus fees imposed by hotel, airline and/or other components
5-0 days - $200 fee per reservation, plus fees imposed by hotel, airline and/or other components
*Additional Terms & Conditions apply regarding transactions including air travel, Halloween Horror Nights, Blue Man Group, VIP Tours and Discovery Cove.
Refunds:
Please allow 2-3 weeks for processing refunds.