You cannot exit the home screen app. The process will be restarted again by the OS.
Ok , And thanks Erel for your quick reply and answer , But what i am looking for actually is that , when i execute myapp , the default launcher becomes "myapp" , that is after i select it from the system dialog box , How can i set it back again to the original "Touchwhiz Home" or whatever original Home screen that comes with Android phone, actually i am looking for the code that will accomplish this task.
I will appreciate any help and thanks again.