title: Get sip address, or username from identity in Teams Calling API
body: <p>We have a calling enabled teams bot, that receives calls. From the data it receives, we want to retrieve who is actually calling. For PSTN calls, this is ok. However, for Teams-to-Teams-calls (or SfB-Teams calls) we get the calling identity as (underneath example is SfB->Teams):</p>
  
  <pre><code>"identity":{
      "@odata.type":"#microsoft.graph.identitySet",
      "onPremises":{
      "@odata.type":"#microsoft.graph.identity",
      "id":"&lt;guid&gt;",
      "tenantId":"&lt;guid&gt;",
      "identityProvider":"None"
      }
  </code></pre>
  
  <p>When all participants live in the tenant of the calling bot, we can retrieve all info (by using the graph API and just query the user with that objectID). But in the case the caller is from another tenant, how can we retrieve the displayname/sipadres for the identity?</p>
  
  <p>For example, if I am being called, my teams client shows a display name. Now if the bot is called, how can it know the displayname (or sip address)?</p>
  
  <p>I've tried to read out more properties using <a href="https://graph.microsoft.com/beta/communications/calls/" rel="nofollow noreferrer">https://graph.microsoft.com/beta/communications/calls/</a>..., however, that returns a 'call not found' consistently.</p>