Points tied to a reservation can’t be transferred so if they are part of a confirmed reservation then that has to be canceled first in order for the points to move.
If you are asking how you can transfer points to someone as a way to pay them for a confirmed reservation they have…then it’s the same as always…
Once you transfer, you have to trust they don’t cancel that trip…you have no recourse. It’s one reason I require payment in full to do a transfer…but the other owners trusted it was safe to do it. If it did it again, it would probably accept 75% upfront since all parties need to call.
I personally would not do this type of trade….I’d want cash for my points..