Google Message Security for Google Apps Administration Guide - Manual (Page 120)

120 Message Security for Google Apps Administration Guide
In large, complex hierarchies, a user administrator can also be assigned at a
strategic managing-organization level in order to manage across several user
organizations. In the following example, the user administrator assigned to the
Operations organization can manage all users in the sub-organizations.
Recommended User Administrator Privilege Settings
For detailed information for each privilege, see The Message Security
Authorization Reference.
User Administrator Privilege Read/Modify Notes
All Standard Privileges
Help Desk
Suspend User
Reset User
View Quarantine
User Settings
Traffic Limits
Change Address
Add Users
Delete Users