License Management, Upgrade and Migration is done via the HP PoeticWeb Portal.
If you only have the LicenseKey you won't get far there, Entitlement Certificate or EON are usually required.
To install a License Key use "omnicc -install_license password" or in GUI under Client-Context rightklick on DataProtector Cell and select "add license".
If you change the IP of your CellServer you have to migrate all your licenses, including Tapedrives, Library and Online-Licenses. They are all bound to an IP-Address and are invalid once this IP is no longer configured on the Server.
One Option that still should work is keeping the old IP on an unused Interface on the Server, that keeps the Licenses vailid and usable.