You can changed the name on a reservation if you are the member who made the reservation.
You can't transfer a reservation from one person's DVC account to another.
You can cancel the reservation, and transfer the points to another members account (if there are no holding status issues), if you haven't had points transferred into your account in the current UY.
There may be other circumstances where you can/can't transfer, but your post isn't clear enough to answer.
No. You can transfer points more than once per Use Year, BUT... you can only transfer in one direction. Therefore, if your first action is a transfer into your account, then you can only transfer points into your account for that UY. If you transfer points out of your account, then you can only transfer points out of your account for that Use Year. When the next UY begins, you can choose again between transferring in/out. Make sense?