admin logon any local win2k profile

How can I as an NT domain Admin log on to any Windows 2000 workstation’s local profile so that I can make changes to that profile without needing to know or change that user’s password? For example, I am changing a network printer and this new printer needs to be the default printer for all profiles on this workstation. I would need to log on to each local user profile to make that change (default printers are profile specific). How can I do this without deleting the profile or logging on asthat specific user?