Many timeshare vacation clubs allow owners to borrow points / weeks from their upcoming use year(s) to book reservations in the current use year. It is important to understand that if you borrow, you will be using your points / weeks from that use year, and will need to wait for those points / weeks to replenish, or borrow again in the following use year.
Different developers set varying rules and restrictions that dictate how this process works, how much usage can be borrowed, and what happens to the usage if the reservation is cancelled or modified, but almost all name-brand timeshare developers allow borrowing from your upcoming use year. Many timeshares allow owners to borrow a portion of your points as opposed to you entire annual allotment, giving you more flexibility in booking for the current use year while still leaving you with some vacation time in the upcoming use year.