Also note they are not exactly speed demons in giving the miles back, e.g. if you have just enough points to go, spend on an award, and then cancel and want to change to another award, with the same # of points they may tell you now you don't have enough points and won't until the credit goes through. Asking nicely they will expedite it a bit. In the same award class- e.g. 60K for Caribbean I don't think they cancel and reissue as long as the award code doesn't differ.