Unfortunately you are not able to change your shipping address after you have made payment and placed your order. Once you have reached the checkout page make sure that you have entered the correct shipping address details.
You can update your shipping or billing address on your My Addresses page.
- Hover over the My Account menu in the upper right hand corner of your screen and click on My Addresses from the drop down menu.
- On the My Addresses page you will be able to edit both shipping and billing addresses, which will be entered as your default details when your checkout in the future.
Wanna know more? Checkout Shipping and Delivery.