Alternative to modify Core XML
You could try creating you own extension with your own xml file that use the same path as the one you want to change.

You should use civix to create the core file of the extension. The new extension needs only 3 files :


info.xml (to be completed after civix has generated it)
yourextension.civix.php (you don't have to touch this one)
yourextension.php (only touch it if you need additionnal customization like hook call)


Then you just have to add a xml file in yourextensionpath/xml/Menu/ that contains the modified menu entry like :

 &lt;?xml version="1.0" encoding="iso-8859-1" ?&gt;
 &lt;menu&gt;
   &lt;item&gt;
     &lt;path&gt;civicrm/admin/scheduleReminders&lt;/path&gt;
     &lt;title&gt;Schedule Reminders&lt;/title&gt;
     &lt;desc&gt;Schedule Reminders.&lt;/desc&gt;
     &lt;access_arguments&gt;administer CiviCRM;access CiviEvent&lt;/access_arguments&gt;
     &lt;path_arguments&gt;action=update&lt;/path_arguments&gt; (also tried with &lt;path_arguments&gt;group=scheduleReminders&lt;/path_arguments&gt;)
     &lt;page_callback&gt;CRM_Admin_Page_ScheduleReminders&lt;/page_callback&gt;
     &lt;adminGroup&gt;Communications&lt;/adminGroup&gt;
     &lt;icon&gt;admin/small/template.png&lt;/icon&gt;
     &lt;weight&gt;40&lt;/weight&gt;
   &lt;/item&gt;
 &lt;/menu&gt;


After activating your extension, you may have to go visit civicrm/menu/rebuild&amp;reset=1 to clean the cache.