title: Facebook account delink or deauthorize facebook app and check status of linking from facebook app
body: <p>My website application having feature login with Facebook login. And for which my app is present on Facebook. Login with facebook is working fine.</p>
  
  <p>But application have feature of linking and unlinking facebook account to Facebook app.</p>
  
  <ul>
  <li>How to check FB account is linked with specific FB app or not?</li>
  <li>And how to unlink FB account from specific FB app if linked (On that user's request )?</li>
  </ul>
  
  <p>("Linked" means we select "Allow" to FB app on request)</p>