Thanks. That's the answer I was hoping for. What's happened with situations the same as this recently is that I called by when I knew it was about to happen, but until you receive the official cancellation notification they won't reboook, despite on this occasion knowing that it's a bit of a no brainer. Just rules of course. So to confirm, you can rebook of any flight where there is any fare class available in the same cabin. e. g. Booked I or R etc, can rebook into up to J, or is it C these days.