How flexible are BA usually if we want to change the destination of our outbound flights booked with Avios/Amex 241/cash when we reschedule them for 2021? Currently flying to Nashville in June but considering trying to change this to Atlanta GA same time next year. What's the likeliest response to this request in the possible scenarios of BA cancelling the flights or us opting to cancel/rebook them with the £35 fee? Thanks