You can always call up and have them change it for you.

Ive changed them right after having checked out and didnt have a problem, my HI went to P&P and my HGI went to miles. This was for stays that were for consecutive nights.

Once when I did have a prob where it went to P&P instead of miles the Diamond desk fixed by giving me triple dipping yep they left the P&P alone and still gave me the miles credit