These things happen! Just log in to your customer account. When you first log in, you should be directed to your "Purchase History" page or you can click on the "Account" icon in the upper right-hand corner of the page at anytime. Click on "Account Details" from the menu on the left of the account page. Below your shipping address, you'll see an option to "Edit". Once the new address information is entered, simply click "Update Address". These changes will be applied to your next subscription order.
If you need to update the shipping address on an order that has already been processed, please contact firstname.lastname@example.org as soon as possible for assistance.