Hi, I am contemplating swapping my points for a travel reward package - but would like to keep the hotel reward voucher for future use. If I get a cat 5 hotel voucher (which I have sufficient points for now), if the hotel I ultimately decide upon is a Cat 6 or 7 can I just pay an upgrade for the difference/ If so what is it? Or will I be limited to Cat 5's.

It must have been asked before but I couldn't find it on searching, so apologies in advance, and thanks for your help. ^