It's my understanding that points can be reallocated under specific conditions.
1. Suppose you have two reservations, one used banked points and one did not. You cancel the one that used the banked points. In certain cases you can reallocate those points to the other reservation and free up the regular points so they can be banked.
2. You purchase a new add-on. You have an existing reservation using next year's points. The add-on came with new current year points. You may be able to bank the new current year points, then use them for the reservation per the same situation as in #1 above.
3. You cannot just reallocate points under these circumstances:
- You made the initial reservation at more than 7 months out using home resort advantage. You cannot later just reallocate and use points from a different resort, thus bypassing the home resort advantage.
- You cancel a reservation and points become holding points. You cannot reallocate them to another existing reservation.
- You have multiple membership numbers, possibly with the same or different use years. You cannot make a reservation under one membership number, and then change it to use points from a different membership number.
To do any of the options in #3 above requires cancelling the existing reservation, and then making a new reservation, subject to availability.
So in your case, assuming that 1)the resale contract has the same use year month as your existing contract and it has been added to your current 'master' contract as an add-on purchase and not as a brand new contract under a new membership number, 2) the new points you purchased have the same resort as the points used for your existing reservation, or if the new points are a different resort, that you did not make the initial reservation more than 7-months ahead, then you should be able to have MS just reallocate the new points to the existing reservation, and free up the current reservation's points. It would not be necessary to cancel and rebook. If any of the above does not apply, then you can only cancel and make a new reservation, pending availability.