I plan on staying in the JW Marriot in HK. However, currently I don't have enough points to book the entire stay with points alone. My plan was to book 3 of the nights with points and pay for the fourth with cash to get the 4+1 deal. If I do this, is it possible to use any subsequent points I acquire (before the stay, after the reservation) to avoid paying for the night? I have a bonus coming up from the CSP, but I'm not sure I'll hit it in time. Even if it means receiving a refund on my card, that's fine.