how to be the last hook_page_alter called? If you implement hook_page_alter in your own module, your hook will be called somewhere between all the other modules.

I am trying to undo something another module is doing in hook_page_alter. Somehow my hook is called before the other one. 

How can I become the last hook to get called ? Or, what is the first hook after hook_page_alter that still uses $page ?
To make your hook last called you can make use of hook_module_implements_alter
like the following:

function MODULENAME_module_implements_alter(&amp;$implementations, $hook) {
  if ($hook == 'page_alter') {
    // Move MODULENAME_page_alter() to the end of the list. module_implements()
    $group = $implementations['MODULENAME'];
    unset($implementations['MODULENAME']);
    $implementations['MODULENAME'] = $group;
  }
}