How to remove user (unregister) push notification

1 
                            $cordovaPush.unregister().then(function(result) {
				    alert("success");
				}, function(err) {
				   alert("error");
				});
2

Is this a question? Please elaborate

3

why ?

The problem is when i unregister and login again with another user id , a new device tokens is created on the old user id