Therea are at least two ways to achieve it.

Proxy shares from old to a new server

[global]
host msdfs = true

[Share]
msdfs root = true
msdfs proxy = \\newserver\Share

Shutdown old server and overtake its shares with alias

[global]
netbios name = newserver
netbios aliases = oldserver

[Share1]
;same Shares as on the old server

[Share2]
;same Shares as on the old server