title: how to unsubscribe from EWS push notification using managed API
body: <p>I am using EWS managed API to do push subscription. Works fine</p>
  
  <p>Now I want to unsubscribe</p>
  
  <p>The managed API docs <a href="http://msdn.microsoft.com/en-us/library/office/dn458791(v=exchg.150).aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/office/dn458791(v=exchg.150).aspx</a> say use <code>service.EndSubscribeToPushNotifications</code>. This is clearly wrong - this function is the pair of <code>BeginSubscribeTo</code>... async operation (reflector confirms this)</p>
  
  <p>I see no obvious method on <code>ExchangeService</code>.</p>
  
  <p>The general EWS docs <a href="http://msdn.microsoft.com/en-us/library/office/aa564263(v=exchg.150).aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/office/aa564263(v=exchg.150).aspx</a> say send this XML, but that its only for pull operations</p>
  
  <p>So what do I do?</p>