WP Default Feed Url Change

I would like to change wordpress feed url. After a little research I find this function (check below).

function remove_feed( $feedname ) {
        global $wp_rewrite;

        if ( in_array( $feedname, $wp_rewrite-feeds ) ) {
                $wp_rewrite-feeds = array_diff( $wp_rewrite-feeds, array( $feedname ) );
        }

        $hook = 'do_feed_' . $feedname;

        // Remove default function hook
        remove_all_actions( $hook );
        add_action( $hook, $hook );

        return $hook;
}

But I don't know how to use this function. Is there any one who can explain it?