National Rail Conditions of Travel Part G - Special Conditions Applying to Season Tickets

41.1 You may change your Season Ticket for another covering a different journey or class of travel provided that the original Season Ticket was valid for one month or more and has at least seven days’ validity remaining. In this case, you will only be required to pay the difference in price between your original Season Ticket and the new one, based on the number of days of validity remaining on your original Season Ticket.

41.2 If your new Season Ticket is for a cheaper journey or class of travel, you will be entitled to a refund on the original Season Ticket, based on the number of days of validity remaining on your original Season Ticket at the time that you ask for your Season Ticket to be changed.

41.3 The validity of your new Season Ticket must start on the day after the original Season Ticket is handed in and must expire on the same date as that of the original Season Ticket. You will not have to pay an administrative charge.