title: Using Graph API how to write Sharepoint "Person or Group" field?
body: <p>I have a Sharepoint Online list with a column of type "Person or Group". I want to make a new entry for such a column using the Microsoft Graph API (eventually from a Teams bot). </p>
  
  <p>My problem is that such a column holds a lookup value into something and I don't know how to get this number. I can successfully get a user object from Graph (/me or /users) but the object returned has an id which is something completely different. How do I link this to what Sharepoint Online requires?</p>
  
  <p>Example: Sharepoint column <code>SG_Responsible</code> of type "Person or Group" as returned by Graph (note it is reported as <code>SG_ResponsibleLookupId</code>):</p>
  
  <pre><code>      "fields": {
                  "@odata.etag": "\"e2977d91-fd6d-4141-8bc6-897f5bbe9840,1\"",
                  "Title": "Test 2",
                  "SG_ResponsibleLookupId": "12",
                  "SG_Description": "This is a Test",
         ...
  </code></pre>
  
  <p>The corresponding user from <code>/users</code>:</p>
  
  <pre><code>        {
              "businessPhones": [],
              "displayName": "John Doe",
              "givenName": null,
              "jobTitle": null,
              "mail": null,
              "mobilePhone": null,
              "officeLocation": null,
              "preferredLanguage": null,
              "surname": null,
              "userPrincipalName": "john@example.com",
              "id": "76a3b5b7-768b-4dde-ba13-6d471aa2c7fd"
          },
  </code></pre>
  
  <p>So how to figure out that this user is user #12 for Sharepoint?</p>