Upgrading Windows NT 2000....

I have to upgrade a Windows NT 2000 Profissional to a Windows NT 2000 Advanced Server....

But, I've been told, there is no way to upgrade.... Only to install the Advanced Server from scratch, re-install SQL Servers, etc, and all applications... :-(((

I'm going to try the upgrade, on top of what is already there, and I'll see if it works.
Then I'll know better how I'll have to do.