You need to look at the KnockingQueue sampleApp in the sampleApps folder. It exacts does the same. When a guest user enters a room which requires owner's permission to enter, his initial role is 5 i.e. LOBBY role and the host gets a message on the Knocking Queue that a guest has entered. Once he accepts and the guest is removed from the queue , he gets into the room with the user role defined for him.
Run the knocking queue example with one instance as host and one as guest and see how the things work.