Thanks Karfa, yes, understood. Not easy to achieve when away from a laptop and working off Iphone. But the issue remains that even once in possession of the booking class, one is still not much the wiser about what will be involved in changing the flight. I often change routings on European tickets: e.g. last week I changed a LGW-GOA into an LHR-ZRH for about £175 which seemed reasonable and proportionate. But you never have a clue until you ask the question which if done by phone invariably involves a length hold whilst they send the query down to fares! And $13k to fly a sililar route an hour later did seem a tad over the top!