WP_User::set_role()
Method: Sets the role of the user.
Source: wp-includes/class-wp-user.php:606
WP_User::__isset()
Method: Magic method for checking the existence of a certain custom field.
Source: wp-includes/class-wp-user.php:272
set_user_role
Action Hook: Fires after the user’s role has changed.
Source: wp-includes/class-wp-user.php:652