Changing IP to hostname is the same as generic changing DB servers.

You need to stop service, change siteadmin.xml in the ''localized'' copy then re-deploy (it might be easiest to change the DB URL in ALL occurances of the file ''siteadmin.xml'' rather than trying to figure out which one is the ''localized one''.)

Bring ALM back up and,
Add a DBServer pointing to NEW DB URL, then
Remove all projects, then fix dbid.xml to point to new DB URL, then restore.

Need to confirm when creating new project that it goes into correct place.

After all projects swapped DB server URL's, DELETE old DB URL from DB Servers list.

WARNING: If you try this by hacking the DB, your qcsiteadmin_db may still not be read from the correct DB server.