Yes, with the LibreView system you are in control of when and how you share your data. If you would like to stop sharing your data with a certain practice (if you switch doctors, for example) log into your LibreView account, and click on the navigation icon in the upper right corner. From the side menu, select Account Settings. Click the My Practices tab and click Remove for the practice with which you would like to stop sharing.  If you would like to stop sharing your data with an app, you can learn how to manage data sharing settings with third-party connections and more in Connected Apps.