Patrons who provide a written notice of cancellation to Group Reservations (1513 Cambridge, Houston, TX 77030) on or before 3 weeks (21 days) prior to the program date will receive a partial refund. No refund will be issued after this date. Program and date changes are not available. The Houston Zoo reserves the right to cancel any program due to minimum enrollment, inclement weather or unforeseen circumstances, in which case a full refund will be issued. Cancellations are official upon receipt of confirmation from the Houston Zoo.