Refer to the contact details listed on your voucher and contact the tour operator for instructions. If it is after hours, contact Viator Customer Service. There is no guarantee that you will be able to join your tour on a later departure, as they may be fully booked. Please allow sufficient time, whenever possible, to reach the departure point in time for your tour. As per the Terms and Conditions on the tour description page of your travel service (where applicable) and the Terms and Conditions located at the bottom of most pages, many travel services carry heavy cancellation penalties.