You use the Authorize Group Reassignment dialog box to specify which users can add or remove users from a group.
On the List tab of the Security Groups (SP) application, select the group for which you want to authorize group reassignment.
Select Authorize Group Reassignment from the Select Action menu. The Authorize Group Reassignment dialog box appears.
Click New Row and enter a value in the User field to authorize a user to reassign members of the selected group. You can also click Detail Menu to select an option and retrieve a user ID.
To authorize multiple users, click Select Users, check the boxes for the users you would like to add, and click OK.
When you are finished authorizing group reassignment, click OK. The dialog box closes, and the system saves your settings.