altering a hook_form_alter function Is it possible to use hook_form_alter() on a hook_form_alter() function already defined in another module?

For example, if I want to alter the output of the following hook from the menu module, can I define a function which allows me to alter the renderable array?

function menu_form_node_type_form_alter(&amp;$form, $form_state) { ... }


I have looked at the documentation but can't seem to find anything that suggests this is allowed/possible.
Not as such, but you can just implement your own version of that alter hook to make the changes you need to, and make sure your implementation runs later on.

To do that you'll need to implement hook_module_implements_alter():

function MYMODULE_module_implements_alter(&amp;$implementations, $hook) {
  if ($hook == 'form_alter') {
    // Push your module's implementations of hook_form_alter(), and derivatives, 
    // to last in the list. This will make it run after menu_form_node_type_form_alter()
    // so you can alter whatever you need to.
    $group = $implementations['my_module'];
    unset($implementations['my_module']);
    $implementations['my_module'] = $group;
  }
}

function MYMODULE_form_node_type_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  // Make changes as usual
}