Using ADModify to change login and pre-2000 name

Launch ADModify using "run-as" and login using a DA account on the domain where the users you are modifying are.

For login name:  Under the Accounts tab enter the attribute:  %'givenName'%.%'sn'%

For pre-2000 name:  

• Click on "Custom" tab
• Put a tick in "make a customized attribute modification
• Attribute name:  sAMAccountName
• Value:  %'givenName'%.%'sn'%