Reordering vertical tabs
Reading between the lines of the other mentioned question and its comments and answer, I've been able to pull out these useful bits of information.


You can do this with
hook_form_FORM_ID_alter
You can find the correct FORM_ID by looking at the HTML source of the form you're working with.  It's given inside the  tag.   Apparently you need to replace the hyphens with underscores.
The code might include something like this:




function hook_form_sublanding_page_node_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  $form['promotion_settings'] = array(
    // something goes here....
  );
}


The code is very incomplete and quite possibly incorrect.  Perhaps someone will complete/correct it.