title: How to merge Call programmatically while other call is running (Conference call)
body: <p>My requirement is like this: Say I am calling a number on that time and I want to call another number programmatically. So far what I have done is: I am able to call to a particular number while some call is already going. For example, suppose I am calling on number 123 and after 1 minute (by using <code>Alarm Manger</code> I trigger an event to call on another number 456 and that is done!</p>
  
  <pre><code>Intent intent = new Intent(Intent.ACTION_CALL);
  intent.setData(Uri.parse("tel:456"));
  startActivity(intent);
  </code></pre>
  
  <p>I am using such intent to call and now I am able to see the screen on my phone with a button to merge the calls:</p>
  
  <p><img src="https://i.stack.imgur.com/dHjRL.png" alt="screenshot of phone"></p>
  
  <p>In this image you can see a button of Merging calls. Now when the user clicks on merge, it will merge all 3 Calls. I want to do it programmatically, not with the user interface.</p>