Change menu link before rendered in mmenu module
You want to implement hook_translated_menu_link_alter() and hook_menu_link_alter(&amp;$item). This hook is not called for all menu items. 

According to the API documentation:

It is only invoked if $item['options']['alter'] has been set to a non-empty value (e.g., TRUE). This flag should be set using hook_menu_link_alter().
Here's an example:

function MODULE_menu_link_alter(&amp;$link) {
  if ($link['link_title'] == 'foo') {
    $link['options']['alter'] = TRUE;
  }
}

function MODULE_translated_menu_link_alter(&amp;$link) {
  if ($link['link_title'] == 'foo') {
    $link['href'] = 'node/5';
  }
}


Some notes

You may want to filter additionally by $link['menu_name']; MODULE_menu_link_alter() is invoked on cache clear for all menus items declared via hook_menu().
For menu items created via web it is only invoked on save, that is, for this code to take effect you need to edit-and-save menu links you want to alter.