title: How do I cancel/exit or escape from PromptDialog.Choice in Bot Framework?
body: <p>The PromptDialog.Choice in the Bot Framework display the choice list which is  working well. However, I would like to have an option to cancel/escape/exit the dialog with giving cancel/escape/exit optioin in the list. Is there anything in PromptDialog.Choice which can be overridden since i have not found any cancel option.</p>
  
  <p>here is my code in c#..</p>
  
  <pre><code>PromptDialog.Choice(
                   context: context,
                   resume: ChoiceSelectAsync,
                   options: getSoftwareList(softwareItem),
                   prompt: "We have the following software items matching " + softwareItem + ". (1), (2), (3). Which one do you want?:",
                   retry: "I didn't understand. Please try again.",
                   promptStyle: PromptStyle.PerLine);
  </code></pre>
  
  <p>Example:</p>
  
  <p>Bot: We have the following software items matching Photoshop. (1), (2), (3). Which one do you want</p>
  
  <ul>
  <li>Version 1 </li>
  <li>Version 2 </li>
  <li>Version 3</li>
  </ul>
  
  <p>What I want if user enter none of above or a command or number, cancel, exit, that bypasses the options above, without triggering the retry error message.</p>
  
  <p>How do we do that? </p>