The void operation can be used to clear the remainder of the reserved amount. Any remainder that isn’t to be captured should be cleared. This is necessary to avoid that these amounts are taken into account in any subsequent authorization request.
The void operation is possible before and after a capture request.
Before will set the (complete) reserved amount to 0. After capture(s), it will only clear the remaining amount.
However, in case an entire order isn’t to be captured we advise you to use cancel instead as this will update the order status to cancelled.