To change the user preferences for the ACS helpdesk account,
you need to first open a search on 'User Profiles', and type 
'ACS' in the user field.  A search on this will bring up the 
User Profile for the ACS.  You basically input the e-mail address 
of the person who will be taking over the Help Desk duties in the 
'Redirect Notifications to...' section which is under 'User Tool Setup'.