Rewrite the url and redirect to this and get the query string values

Hi Team,

I am creating a url by add_query_arg() by adding some query string to the url in a ajax call. So the new url will be like this https://example.com/seminar/?id=12 , where seminar is a page having page slug seminar.

I’m sending this url in ajax respone and redirecting to it.

So, I want that the url should automatically turn into like this:
https://example.com/seminar/12

and I also want to use id parameter.

Currently I’m coding like this:

add_action(‘init’, ‘custom_rewrite_rule’);
add_filter(‘query_vars’, ‘wpse12965_query_vars’ );
add_action( ‘init’,’my_flush_rules’,50 );

// flush_rules() if our rules are not yet included
function my_flush_rules(){
$rules = get_option( ‘rewrite_rules’ );

if ( ! isset( $rules[‘seminar/([^/]+)/?$’] ) ) {
global $wp_rewrite;
$wp_rewrite->flush_rules();
}

}

function wpse12965_query_vars( $query_vars )
{
$query_vars[] = ‘id’;

return $query_vars;
}
function custom_rewrite_rule() {

add_rewrite_rule(‘seminar/([^/]+)/?$’,’index.php?pagename=$matches[1]&id=$matches[2]’,’top’);

}

But it seems like not working. Niether the url is changing nor the id parameter is adding to query_vars[] in $wp_query variable.

Anyone, Please suggest.

Thanks,
Darik