After placing an order, there is no option to change the coupon code. However, rest assured that we will honor the discount with the higher amount and promptly refund the difference to you
Ex. A customer applied a 10% off coupon to the purchase, which resulted in a $5 discount. However, the customer had another coupon amounting to $10 off. Super will honor the 2nd coupon and refund the difference of $5.