anchor.diff:  <tr>
     <td>422 Unprocessable entity</td>
     <td>
  -    May be returned if the requested plan change is not supported or if the request can not currently be fulfilled due to the state of the instance (eg. instance utilization is over the quota of the requested plan). Messages returned by the broker will be passed through to the client. Refer to <a href="#broker-errors">broker errors</a> for the expected body.
  +    May be returned if the particular plan change requested is not supported or if the request can not currently be fulfilled due to the state of the instance (eg. instance utilization is over the quota of the requested plan). Broker should include a user-facing message in the body; for details see <a href="#broker-errors">Broker Errors</a>.
     </td>
   </tr>
   </tbody>
   </table>
   
  -All other status codes will be interpreted as an error and Cloud Controller will inform the user that the update service request failed.
  -
  -We have chosen to require empty JSON in the response for future compatibility; it will be easier to add fields in the future if JSON is expected rather than to support the cases when a JSON body may or may not be returned.
  +Responses with any other status code will be interpreted as a failure. Brokers can include a user-facing message in the `description` field; for details see [Broker Errors](#broker-errors).
  +
  +##### Body #####
  +
  +All responses must include valid JSON in the body. This is for future compatibility; it will be easier to add fields in the future if JSON is expected rather than to support the cases when a JSON body may or may not be returned.
  +
  +For a success response, the expected response body is `"{}"`.
   
   ## <a id='binding'></a>Binding ##
   
  
positive.code: <tr>
    <td>description</td>
    <td>string</td>
    <td>An error message explaining why the request failed. This message will likely be forwarded to the person initiating the request.
  </td>
  </tr>
  </tbody>
  
negative.code: 
  ### Response ###
  
  <table class="nice">
  <thead>
  <tr>
    <th>Status Code</th>
  