I am guessing it has to do with the CC since you had to prepay for your meal, if you wanted to cancel your ADR then they would have to refund the money on your CC, therefore they would probably would have to have you on the phone to do so....however I am just speculating.
I am kind of thinking of doing a switch, we have CRT for dinner and was thinking if I could switch it to Breakfast (if it is available) how I would go about doing it. Since we already prepaid for the dinner I am guessing that I would have to call and change it to the breakfast. Then since the dinner is more expensive than the breakfast would they have to credit my CC first then recharge for the breakfast or would they just credit back the difference? I am almost to the point to not even worry about it and just let it be because it seems like too much of a hassle.