Hello, just to confirm since there is a user which will be replaced and I need to change both name surname details as well as username and password. Shell I proceed straight away without any worries since the DC knows the user by its SID and not by the friendly names, am I correct in saying this or is there something that really changes like for example group membership, permissions ? Thanks

You are correct. You can change the surname, given name, Common Name (value of the cn attribute), display name (full name), "pre-Windows 2000 logon" name, and password and nothing will be affected, including group memberships. If you change the "pre-Windows 2000 logon" name the user must logon with this new name. If you change the "Common Name" this will change the name in ADUC in the field labeled "Name". Those are the only things I can think of that would be affected. Richard MuellerMVP ADSI

Forgot to ask.... Even the local profile on the pc will remain the same since the login will be changed and it will log with the new credentials ? I do not think so and I will need to transfer all local files from one profile to the other right ?

I forgot to mention, the local profiles are stored in the registry by SID, which does not change when you rename the user. You can see them in the registry under the key HKLM\Software\Microsoft\Windows NT\CurrentVersion\ProfileList. Richard MuellerMVP ADSI

that is good news, so since the SID is not changed all local files including Desktop will remain exactly the same. Basically as long as you do not delete and re create the account you can change whatever you need on an account and it will always remain with the same settings. Thanks a lot

The only problem I got is that the local profile remained with the old username and did not update to reflect the new user, can this be renamed or it can give problems for example loosing the profile.