If you are logged in and you have your licenses registered under your account, you can may just log out.
If you are not logged in and you have installed some preset packs from Videohive.net, these licenses cannot be removed - they are bound to your computer. However, you can transfer these licenses to your Mister Horse account and from then on you can just login/logout of the computer.
If you do not have a Mister Horse account you can register one here.
Where can I log in?