Credit values for STA Travel are the remaining net contract value of the unflown sectors. This means that the margin earned by the original issuing branch is retained by them. Passengers may get the highest return of money by refunding their tickets at the branch of original issue. Refunds are calculated using the same formula as credit values, but the difference is the sales mark-up of the issuing branch, so the refund depends on that margin plus the contracted level of Cancellation Fees. Because these vary so much it is important that no estimation of the refund value is given. The Credit Value Fee is a maximum USD50 per ticket. This is retained by the Travel HELP branch dealing with the credit value. In the event that the change to the ticket will not add to its value, and that the same airline contract is being used, it may be possible to reissue the ticket to change a sector as shown in the Reissue section. There must be no change to carrier, class of booking, or date if that changes the flight into a higher season. No additional sectors may be included. When a passenger request a change to an onward sector which may be common rated, the credit value form should be completed to include the information on the requested new sector. The reissue form should not be used, and the passenger should be advised only that a value for the new ticket is being obtained. If the Help desk confirms that a reissue may be used, no further changes may be made without repeating the procedure. Inter Divisional/Company credit value communications are solely between HELP desks.