Reservations are obligatory and subject to availability at the time of request. Gift vouchers are nominative and non-transferable (the name of the beneficiary is valid). They cannot be endorsed, exchanged or reimbursed. They may not be exchanged for cash, in whole or in part, nor may they be resold. They cannot be used in installments. If the cost of a service exceeds the value of the voucher, the difference must be paid for by another means of payment. In the case of a service that is less than the value of the voucher, the difference will not be reimbursed.