Along the same lines, what is anyone's experience with switching airlines re: a specific card. For example, I have an AMEX registered with NW, but now want to register it with AA. Do I need to cancel the NW registration and, if so, will it jeopardize the miles that are pending?
Also, any experience with changing the FF number associated with a registered card? For example, if I want to change my AMEX from my NW FFR account to my child's NW FF account.