Hi Robert,
The Hostname change is not supported in CCM Versions prior to CCM 6.1(2):). I have dealt with some "rebels" who defied these threats and regret the fact they did. You can change the IP Address (see below docs);
Note: It is not supported to change the hostname on the Cisco CallManager server because the Structured Query Language (SQL) database does not support the hostname change. This is because SQL uses the server name for many of the tables related to Cisco CallManager and exchanges this information as such with the operating system. When SQL server is installed, it binds the database to both the machine and Cisco CallManager server names. If this is changed, the database does not replicate properly since the new Cisco CallManager or machine name is not updated correctly by SQL. **If a hostname change is inevitable, then the entire Cisco CallManager must be rebuilt.
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080094601.shtml
Prior to Cisco Unified Communications Manager Release 6.1(2), you cannot change the host name of either the publisher node or subscriber node after it is installed. If you must apply a new host name to a server, you can delete the server from Cisco Unified Communications Manager Administration (System > Server) and then reinstall the server with a new hostname. Also, be aware that a DRS backup that you take from a server with a particular hostname cannot be restored on a server (either a publisher or subscriber node) with a different hostname, even after you reinstall that node.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/install/6_1_1/ipchange/ipchg611.html
Changing the Hostname of Cisco Unified Communications Manager Servers
Starting with this release (6.1(2)), you can change the hostname of the first node or any subsequent nodes in the Cisco Unified Communications Manager cluster. You can only change the hostname of the first node from a subsequent node. The Cisco Unified Communications Operating System Administration user interface populates the hostname field on the Ethernet Configuration window and the Publisher Configuration window with the existing values. You can change the IP address or hostname of servers using the set network cluster publisher ip or set network cluster publisher hostname CLI commands.
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Caution Resetting the hostname will cause your system to reboot and you may lose connectivity with the first node and the network. Before attempting to change the hostname of a Cisco Unified Communications Manager server, refer to the Changing the IP Address and Host Name for Cisco Unified Communications Manager Release 6.1(2).
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/rel_notes/6_1_2/cucm-rel_note-612.html#wp401012
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/install/6_1_2/ipchange/ipchg612.html#wp185050
Hope this helps! Cheers!
Rob
