Upgrade Windows Server 2003 editions

I've been looking it up a bit but couldn't really find what I want. My question is, is there a way to upgrade a W2K3 Entreprise edtion server to W2K3 Datacenter edition without using the CD/DVD? I already have the license key for it I'm just want to know if there is a way to do it like in W2K8 with DISM. Any help would be greatly appreciated.