You can change your delivery mode by logging into My Account and clicking on the "Edit Shipping" link located just under the Delivery Address.
This may result in a balance due on your order which will need to be paid before your order will ship out. You'll be able make payment in My Account if this is the case by clicking on the Make Payment button.
*Note that you may need to refresh your page to see this option.
If the change results in a refund, we'll submit that back to the same card used for the order, shortly after the order has shipped.