Yes, you will need to move or cancel the 11:30 FP in order to move the 12:30 to that time. I would modify the FP you have for 11:30, change it to the afternoon or evening, just to get it out of the way. Then move the one you have at 12:30 to the earlier time. Then you can move the first one to a better time.
ETA - that is if there are earlier time available.