Since it hasn't been served yet, you should be able to cancel it.
Tips
usage
Pairs with 加菜 (order more) and 上菜 (serve a dish). The 退 prefix marks 'undoing' a transaction: 退款 (refund), 退货 (return goods), 退票 (refund ticket).
culture
In China it's acceptable to 退菜 if the food is wrong, cold, or has a hygiene issue, but face culture means most people just complain on review apps instead.
