Unfortunately, promo codes cannot be combined or modified after an order has been submitted, nor can multiple promo codes be applied to a single order at checkout. Only 1 promo code can be applied per order at checkout. Once an order is submitted, we are unable to swap the promo code applied to your order. You are welcome to place a new order and use the second promo code to benefit from the discount.
Please ensure to review your order summary prior to completing checkout to make sure you are satisfied with the promo code offer you've applied. If you have any questions, please feel free to contact us. :)