If you want to prevent a user from logging on to the system but want to keep the user account for later use, you can disable the account.
You can activate the account when the user is again permitted to log in to the system.
To disable or activate a user account:
On the Users tab, select the user account
Click Edit User Account
Do one of the following:
To disable the account, clear the check box Active.
To activate the account, select the check box Active.
4. Click OK.
Note: Domain-based (LDAP) users cannot be deleted or removed with System Manager.