gracefully restarting ApplicationRunner

I have a WAMP application working using twisted, ApplicationRunner and a subclass of ApplicationSession. One thing that’s missing is to gracefully restart when the connection parameters change. There are external events in our broader system that change the URL that the WAMP application should connect to. I’m handling those events already in the WAMP app, but I don’t see a way to shut down the ApplicationRunner and loop around to create and start a new one with the updated connection URL. What am I missing here?