So I travel from Gatwick airport to Barnes station, and I have to stop and change trains at Clapham Junction. I pay £12 off peak and £17.60 on peak for single and open return (I have a railcard). And the ticket is labelled as Gatwick to Barnes and Barnes to Gatwick - however I want the return ticket to go to Crawley station instead of Gatwick which is only 2 stops after Gatwick, is there a way I can do this without having to buy a seperate fare just for the two stops? It would be alot easier if I could change the tickets return station but I can't see how - and buying two singles is too expensive. Any advice?