Always reachable for calls on mobile

I would always like to be reachable by phone via the RC mobile app. However, when I'm travelling and don't have a desktop app open and my smartphone is locked, my status is automatically set to ‘offline’. However, the status should still be set to ‘available’ so that I can always be reached. Is it possible to configure RC in this way or can you really only be reachable when an app is actively open and status set to available?