I had points transfer to my account, I transferred a week to a renter and I exchanged a week with a deeded owner of a fixed week with my points reservation. We each filled out our own form. Everything was done via the online form. On the week I transferred to a renter, the form was filled out Friday and moved over by Tuesday. When using the form for weeks, once the transfer takes place, neither party receives an email notification. You have to do a find reservation to see it was done. With the transfer of a week using the form, after the transfer takes place, the rewards number of the original reservation gets wiped out and it is blank. The person who the unit is transferred to, can put in their rewards number. On the unit I reserved using points and transferred to a renter, the reservation is removed from my Marriott.com account because the rewards number is removed but it stays shows in MVCI points reservation but with the new persons name in it.
Even though the process is easy, it still is easier to get onto Marriott.com and make the change (for weeks). The added benefit is your rewards number stays in and there is a chance you can get the credit. More times than not, I get the credit.