title: Convert DateTimeOffset to DateTime and add offset to this DateTime
body: <p>I have <strong>DateTimeOffset</strong>:</p>
  <pre><code>DateTimeOffset myDTO = DateTimeOffset.ParseExact(
                        &quot;2015/01/15 17:37:00 -0500&quot;, &quot;yyyy/MM/dd HH:mm:ss zzz&quot;, 
                        CultureInfo.InvariantCulture); 
  Console.WriteLine(myDTO);
  </code></pre>
  <p>Result =&gt; <strong>&quot;1/15/2015 17:37:00 -05:00&quot;</strong></p>
  <p>How convert to DateTime and add this offset <strong>&quot;-0500&quot;</strong> in the resulted DateTime</p>
  <p>Desired result =&gt; &quot;<strong>1/15/2015 22:37:00</strong>&quot;</p>