When you uninstall or remove the 2nd Line App on your device, your regular phone number still works as usual. The special 2nd Line number you get in the app doesn't affect your real phone number connected to your SIM card or plan.

Please Note: If you uninstall  2nd Line App, your app account won't be deleted. Your 2nd Line number or numbers you bought and your subscription will stay active in your account until they expire, even if you remove the app.