If you change your booking to a date with a lower price, you will not receive a cash refund for the difference

How the remaining balance is handled depends on your specific booking type:
Reservations with Flex Booking: If there is a decrease in price when you change your date, the remaining balance will be placed on a voucher that can be redeemed in-house during your visit. This same policy applies to Black Friday Flex bookings.

If the price of the experience you select is lower than the value of the gift card you are using at the time of booking, no refunds or credits will be given unless otherwise stated.
 

Standard Reservations made without the Flexible Booking option, the date is generally not amendable, and these bookings are non-refundable at any time. Additionally, the cost of the Flexible Booking option itself is non-refundable.