Part paying occurs when the customer does not have enough money on their eGift Card to pay for the complete order.

For example, your order could be $50, but you only have $40 as the remaining balance on your eGift Card

In the event of this, you would follow the steps covered  in "Redeeming your Gift Card (Using the Gift Card to make the purchase)"

The balance of the eGift Card card will be applied to the order and then you can choose how the remaining will be paid.