title: Request a MS Graph Access token from Middleware
body: <p>I'm trying to request MS Graph API from an API Middleware, in ASP.Net, to create programmatically Office Planners on specific api calls.</p>
  <p>Customers are logged in to the frontend application via Azure AD SSO (using adal).
  This access token allow users to authenticate to my api.</p>
  <p>Now, i want to request a MS Graph access token from this API access token, to create the planners from the authenticated user account (on behalf of).</p>
  <p>How can i proceed ?</p>
  <p>Could the OBO flow (On-Behalf-Of flow) work in this case ?</p>