Simply follow these steps:
1.Go to the web app and login with your details.
2.Open your Account settings menu and navigate to the Account details tab.
3.At the bottom of the page, you'll find the option to revoke access or change accountant:
4. Remember that if you revoke access your account will move to "expired trial" state and your items will no longer be processed. To activate, simply switch to "Subscription" tab and subscribe to the desired plan.