AudioRoutingManager audioRouting = AudioRoutingManager.GetDefault();
    public AudioRoutingEndpoint ChangeAudioRoute()
    {

       var currentEndPoint= audioRouting.GetAudioEndpoint();
       switch (currentEndPoint)
       {
           case AudioRoutingEndpoint.Earpiece:
           case AudioRoutingEndpoint.Default:
               return AudioRoutingEndpoint.Speakerphone;

           case AudioRoutingEndpoint.Speakerphone:
               return AudioRoutingEndpoint.Earpiece;

               default:
               throw new OperationCanceledException();
       }
    }

    public void SetAudioRoute()
    {
        audioRouting.SetAudioEndpoint(this.ChangeAudioRoute());
    }