You can change the shipping address in My Orders page.
Please note that you can only change it after the payment is complete.
■ How to change your shipping address
[My > My Orders > Order > Details]
※ If you've paid via PayPal, you cannot change the shipping address once you've completed the payment as your initial order information would have been transferred. In this case, please cancel your order and place a new order with the address you want to change to.