Explanation/Reference:
Explanation:
Change the Domain Value
Follow this procedure if you want to change the domain value (from one valid domain value to another valid IP proxy domain value).
This procedure is applicable if you have a DNS or non-DNS deployment.
Procedure

Stop the Cisco SIP Proxy, Presence Engine and XCP Router services on IM and Presence on all

nodes in your cluster.
Step 2
On the publisher node, perform the following steps to configure the new domain value:
a. Select IM and Presence Administration > System > Cluster Topology.
b. In the right pane, select Settings.
c. Configure the Domain Name value with the new domain. a. Select IM and Presence Administration > System > Service Parameters, and select the Cisco SIP Proxy service.
b. Configure the Federation Routing IM and Presence FQDN with the new domain.

then select Save.
Step 3

On all nodes in the cluster, use this CLI command to set the new domain:
set network domain <new_domain>
This CLI command invokes a reboot of the servers.

Step 4
On all nodes in the cluster, manually start the Cisco Presence Engine and Cisco XCP Router services after the reboot is complete (if required). Step 5 Manually regenerate all certificates on each node in the cluster.
Cisco 400-051 Exam
Reference:
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/im_presence/ip_address_hostname/9 _0_1/ IM_P_IPChange/sip_domain.html