Hi,

I'm wondering if I make a reward booking (on marriott.com) using either points or night certs (i.e attach the cert at book time), can I still switch to the other one later (i.e. booked using points but later use certs for the stay and have the points back; or booked using certs but later use points for the stay and have the certs back)?

Interested in situations both before and after the "free cancellation deadline".

Reason for asking: The certs I have are higher cat than the hotels I'm booking but would expire in a few months (and have already had their expiration dates extended once), so not too sure about using them now or not.

Thanks!