sticky header js

i cant get this to work
add_action( ‘wp_enqueue_scripts’, ‘wp_change_sticky_header_script’, 100 );
function wp_change_sticky_header_script() {
wp_deregister_script( ‘avia-sticky-header’ );
wp_enqueue_script( ‘avia-sticky-header-child’, get_stylesheet_directory_uri().’/js/avia-snippet-sticky-header.js’, array(‘avia-default’), $vn, true);
}

or this
function jmb_avia_sticky_header()
{
wp_dequeue_script(‘avia-sticky-header’);
wp_deregister_script(‘avia-sticky-header’);

wp_register_script(‘avia-sticky-header’, ‘/wp-content/themes/enfold-child/js/avia-snippet-sticky-header.js’);
}
add_action(‘wp_enqueue_scripts’, ‘jmb_avia_sticky_header’);

the deregister doesn work….