Upgr. from Win2k Pro to Win2k Server

My problem is that I want to upgrade/promote a Win2k Professional to Win2k Server. It doesn?t seem simple because the message I get is that Win2k Pro can?t be upgraded to Win2k Server. Is that right? It seems to be illogical to have to make a clean install on this machine. There aught to be more compatibility built in this software.

Thnax in advance.
?ttar