public function removeAdministrator($id)
    {
        $administrator = Agent::find($id);
        $administrator->ticketit_admin = false;
        $administrator->save();

        // Remove him from tickets categories as well
        if (version_compare(app()->version(), '5.2.0', '>=')) {
            $administrator_cats = $administrator->categories->pluck('id')->toArray();
        } else { // if Laravel 5.1
            $administrator_cats = $administrator->categories->lists('id')->toArray();
        }

        $administrator->categories()->detach($administrator_cats);

        return $administrator;
    }