Is it able to combine FN and points reservations? (And then apply a TSU if a standard suite is available)

If it's possible, do I need to call the CS or the Twitter team can make it?

I know usually it doesn't, but I booked it before the hotel is playing games with rewards availability (2FN+1 night with points), but now it's impossible to get any suite availability for even that 1 night stay.

Thanks!