Unless you define a user name or UID number that conflicts with an existing one, you should never need to modify a user account's login name or UID number. Use the following steps if two user accounts have duplicate user names or UID numbers:
If two user accounts have duplicate UID numbers, use Admintool to remove one account and re-add it with a different UID number. You cannot use Admintool to modify a UID number of an existing user account.
If two user account have duplicate user names, use Admintool to modify one of the accounts and change the user name.
One part of a user account that you can change is a user's group memberships. Admintool's Modify option lets you add or delete a user's secondary groups. Alternatively, you can use the Groups window to directly modify a group's member list.
You can also modify the following parts of a user account:
You can customize the user initialization templates in the /etc/skel directory and then copy them to users' home directories.
You can use Admintool for password administration, which includes specifying a normal password for a user account, enabling users to create their own passwords during their first login, disabling or locking a user account, or specifying expiration dates and password aging information.
Occasionally, you might need to temporarily or permanently disable a login account. Disabling or locking a user account means that an invalid password, *LK*, is assigned to the user account, preventing future logins.
The easiest way to disable a user account is to use Admintool to lock the password for an account. You can also enter an expiration date in the Expiration Date field to set how long the user account is disabled.
Other ways to disable a user account is to set up password aging or to change the user's password.