How to Cancel Your WoW Subscription
To cancel your WoW subscription,
1. Go to the Battle.net Account page. If necessary, log in to your Battle.net account.
2. In the left-hand menu, click “Games & Subscriptions”.
3. In the “Game Accounts” box, find the account whose subscription you’d like to cancel. An active account will have a “Next Billing Date”.
4. Click the blue “Manage” text in that account’s row.
5. Click the blue “Cancel Subscription” text.
6. Answer the (required) first question in the “Cancellation Survey” box. All of the subsequent questions are optional.
7. Scroll down and click the “Continue” button.
8. On the final page, click the blue ‘Cancel my Subscription’ button.
You will still be able to play this WoW account until the day and time on which its subscription ends.