A deposit is consumed by being applied automatically at the time of check out. It can only be consumed for the reservation it was paid for. The Paid Amount for the deposit will be automatically added as a credit in the cart and subtracted from the subtotal of the reservation:
On the receipt the consumed deposit looks like this:
Sometimes, the deposit amount paid will be greater than the subtotal of your shopping cart. When that happens, you will be presented with 2 options.