I have configured ServiceDesk to notify a user when a request has been closed.  I would like to change the status of a request from "Closed" to "Open" if a user replies to the notification so that the request appears in lists of open requests.  I assumed that I could use a buisness rule to achieve this, but I do not seem to be able to create a business rule based on the value of the "Status" field.  Am I missing something?  Can this be done in some other way?