The simplest way is to copy a few files from an existing server that's using <old license id>.

1. Grab the <old license id>.snf file, identity.xml file, and getRulebase script.
2. On the <new license id> server:
      1. Stop SNF
      2. Replace the files you grabbed above.
      3. Start SNF

The <new license id> server should now be running SNFServer again under the new identity.
Check with SNFClient -status.second -- you should get appropriate XML data.
Check again with SNFClient -status.second -- you should get appropriate XML data again -- slightly different counts.