A 48 hour cancellation notice in advance of the trip departure time is required for a refund. If an attempted cancellation is on less than 48 hours advance notice and due to a medical illness, a written statement from a local physician or medical clinic is required. A guest may re-schedule an excursion without a cancellation charge if the new excursion is taken within 72 hours of the booked excursion if space is available. Any price differential in the originally booked excursion and the re-scheduled excursion shall be paid by or refunded to the passenger as the case may be.