Originally Posted by
KARFA
I think it is section
16.1 & 16.2 here which are applicable.
The change of route part is correct for what you have been told - I know that PHX and DFW are slightly further than ATL but they will all be in the same band and that is how the avios levels are set. Actually, I don't think you would be able to change it anyway as 16.1 clearly states:
All permitted changes are subject to capacity limitations and may not be made after the time 24 hours prior to the scheduled departure of the first flight in the Reward travel itinerary
This was what I thought as well, so at less than 24 hours or once you have started flying the booking you can't change it anyway. Cancellation is the same, less than 24 hours and you don't get any avios refund.
I have made changes after departure before. I was able to change JFK to IAD last year. Also the rep just told me I could make a change now within the same band.