title: Actions on Google - How to revoke account linking?
body: <p>Here is my situation : 
  I develop a Google Assistant application with Dialogflow. 
  My service needs user to be connected to their account. So I implemented the OAuth 2.0 Authorization Code Flow as explained in the <a href="https://developers.google.com/actions/identity/oauth2-code-flow" rel="nofollow noreferrer">account linking Google guide</a>.
  Now my users can link my Assistant app to their account to vocally make action on it. It's work great, no problems with that. </p>
  
  <p>My question is here : I have to give the possibility to my users to revoke the link between Google Assistant and their account. To do so I remove authorizations on my side and naturally returns a 401 response "invalid_grant" when I receive a request from the Assistant. My question is how can I notify Google that an access token has been revoked and that the user needs to relink the Assistant App to his account. Usually the assistant notify the user by the following : </p>
  
  <blockquote>
    <p>It looks like your MyAppName account is not linked yet</p>
  </blockquote>
  
  <p>Without that, Google keeps trying to send me requests until he does a refresh token and receive a 401 response. Is there an API or a way to directly revoke authorization on the Google Assistant side? </p>
  
  <p>Thanks for any answers ;-)</p>