I had to cancel an award ticket a couple weeks ago about 48 hours before departure. Delta allowed me to cancel the flight but stated that I would not get the miles back because it was within 72 hours of departure. I was not aware of this rule change. Luckily I did get my miles back and the fees I paid were refunded to my Amex. But it did take 3-4 days for this to occur because I understand a ticketing agent had to manually cancel and refund my trip.