When the store gift card is not through Givex a custom checkout pane can be enabled so that both the store gift card and credit card information can be collected for the order.
STORE GIFT CARD - USING CUSTOM CHECKOUT PANE
Stores can use the Custom Checkout Pane #1 to collect the store gift card number from their customers during checkout. Customers will also be required to enter a different form of payment as well. This way, if the gift card doesn't cover the balance of the order, you already have other payment information. If you don’t have this pane enabled on your site, please contact firstname.lastname@example.org
If credit card is the additional form of payment, the credit card would be authorized for the full amount of the order, and your staff reviewing/processing the order would need to be responsible for verifying the store gift card and adjusting the balance before capturing the authorization.
If you want to see what the custom pane looks like, you can see it live on this members website redballoonbookshop.com by adding an item to the cart and going to checkout, however, this is a LIVE website, so please do not complete the order.
With this option enabled, going forward, staff reviewing orders will want to pay careful attention to whether or not a store gift card has been indicated. If so, the key here is to apply a partial payment to the order, before you charge the card. This will drop the chargeable balance. To modify this order, first, click the "Payments" tab at the top, right (the row of grey tabs along the top).
On the next page:
Change the Payment method to "Gift Card"
Input the gift card amount in the "Amount" box
Add a comment (optional... in this case I'd recommend "gift card payment")
This will drop the order balance by the entered gift card amount.
Then, go back to the Order View page, and process as usual.
The credit card will only be charged for the remaining balance, NOT for the entire authorized amount.