I had a similar question, so this thread is appreciated. If I have a one way award flight (say LHR-BRU), it seems I could change that award flight to LHR-AMS since they are in the same zone. But when it is indicated that space must be available, does that mean specific award space? My need would likely be to do this at the last minute, so if I can change destinations easily, this is extremely helpful for me. If award space needs to be available, then last minute changes are less likely to be workable, even though the plane may have many available seats. Any experiences with this type of scenario?