You need to create an action using the hook provided by the other plugin, you did not provide this hook name. Also, the details of how to use this hook are not clear. I also do not know what will be is save ID. Is it just the ID? Is there anything to tell you the object type that is being saved? You will need this information to call acf_form() for anything other than a post. Most of the following is a guess based on the information you’ve provided, more than likely it is not 100% correct.
add_action('some-hook-name', 'my_modify_dd_form');
function my_modify_dd_form($form_id, $post_id, $form_settings) {
$args = array(
// assuming that this is going to be saved to a post
'post_id' => $post_id,
// other acf form settings as needed
// see https://www.advancedcustomfields.com/resources/acf_form/
);
acf_form($args);
}
