Demo of 2 way communication between an Apple Watch app and it's parent iOS app. Information can be passed to the iOS app, which then "replies" back with a response to the watch extension and updates the UI for the watch app. This is an add-on to my original Send Data to Parent iOS App tutorial.
See full 2 way communication tutorial on http://www.kristinathai.com/watchkit-tutorial-communicate-from-parent-app-back-to-watch-via-reply