You have a set of datasets accessed via Fileshare server server1. They are in c:\fsdir\datasets, where c:\fsdir is the Fileshare directory for server1. You do not move the datasets, but you stop the server and restart it with a different name, server2. To update the catalog:
set mfsyscat=c:\catalog\catalog.dat set mfalloc_loc=$$server1\datasets mvspcrn $$server1 $$server2