How to unregister a device from ionic push

I’m just wondering if anyone would be able to clear up how push.unregister() works. In the docs it simply says to unregister a device just call the following, push.unregister(); however whenever I try to use this I get an 422 (UNPROCESSABLE ENTITY) error. Token registration works fine but even if I was to remove the registration code in it’s entirety I’m still able to send push notifications. If anyone could clear this up for me it would be great.