Quick answer: Unfortunately, no. Throne processes orders quickly so gifts don't sit in a queue, which means there's no window to edit or cancel once you've confirmed. It is worth double-checking the details on a gift (size, color, quantity) before you send it.
This is also outlined in our Terms of Service, which you accept before you purchase an item.
If a payment failed
If you saw a charge but the gift didn't go through, that's a temporary authorization hold from your bank, not a completed payment. It drops off on its own, usually within 10 business days. See "I was charged but got no confirmation."