Rename Exchange 2003 Organization

I am currently running Exchange 5.5 on NT4. The plan is to upgrade to Exchange 2003 in the near future and I need to rename the organization and default site. I would like to complete the migration first and then renam the Organization and Site.

Does anyone know if there is a method of doing that in Exchange 2003 or if there was a method in Exchange 2000.

Thanks in advance.

Oli