Originally Posted by
Schnit
This is your answer. Book a dummy one further out for the first certificate, this way you use the 40k. Then cancel that reservation to get the 35k back. Now book using the 35k.
Its annoying but the easiest way to do it
The potential problem if you do this is having two reservations for one night each and not getting the same room both nights. Likely the hotel can work it out, but I would prefer to call Marriott reservations and have them apply the FNA’s the right way on a single stay reservation.