After you authorize a user to a client, you can take back the authority always. We explained the process in this article.
If you want to remember how to authorize a user to a client, you can read this article.
First, go to the Client Settings->Client tab.
2. Select the client that you want to manage who is accessing.
3. Click the "User Access" tab. You'll see a user list that shows who has access to the client's data.
To unauthorize a user, click the "Unauthorize" button.
4. To get your confirmation, a popup will show up. If you are sure that to unauthorize the user approve the deletion.
5. After you approve the process, the user will not see the client's data anymore.
You can reauthorize the user anytime you want by clicking the " Select User" button, or read this article.