<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by ExMo:
Well, almost. You can change the first segment but it will require a ticket reissue with whatever fare and rules are then in effect. There is no OW charge for the reissue but some airlines (notably BA) have been charging a service fee for ticket changes.</font>
According to the rules, travel originating in areas 2/3 don't require a ticket reissue for changes to the first segment.