I bought two train tickets online but because they had to be bought in separate transactions, I ended up with seat reservations in different carriages. I was in Stratford this morning so I decided to visit a ticket office to ask for one of the seat reservations to be moved closer to the other seat reservation. I went to Stratford International Station, but the Southeastern staff there told me that they couldn't handle seat reservations. Perhaps I made the wrong call and I should have gone to one of the ticket offices at Stratford Station - are there two ticket offices; one TfL Rail and one GA? My question is, how do you know which ticket offices can handle seat reservations? I'm happy to travel to a ticket office that can handle seat reservations, but despite researching station facilities online, I can't find any way of determining which ticket offices can or cannot handle seat reservations.