Hi Jeff,
This is not something we've done so I can't add any first hand experience (sorry)
but it does appear from the doc you linked that that config changes required to do this
would depend on whether you are moving the Pub or Sub
If you are changing the IP address for a Pub;
Step 5 
If Digital Networking is configured, remove the publisher server from the digital network. See the "Using Digital Networking" chapter of the System Administration Guide for Cisco Unity Connection Release 7.x at http://www.cisco.com/en/US/docs/voice_ip_comm/connection/7x/administration/guide/7xcucsagx.html.
Caution
Readding a server to a digital network can be a time-consuming process. Ensure that you thoroughly understand the work required to readd a server to a digital network before you continue with this procedure. If you are changing the IP address of a Sub it looks like the changes would be related to SMTP;
Configuring SMTP Access for Cluster Subscriber Servers
When you create a Digital Network that includes a Cisco Unity Connection cluster server pair, you join only the publisher server of the pair to the network. In order for all locations on the network to communicate with the cluster subscriber server in the event that it has Primary status, you must configure all network locations (except for the publisher server that is clustered with the subscriber server) to allow SMTP connections from the subscriber server.
Directory updates are only replicated from the cluster publisher server. SMTP connectivity is needed so that locations can continue to receive user message traffic while the publisher server does not have Primary status. Replication resumes as soon as the publisher server has Primary status again.
For example, a network has the following three locations:
•ServerA, which is not a cluster member
•Cluster 1, which is made up of ServerB, a publisher, and ServerC, a subscriber
•Cluster 2, which is made up of ServerD, a publisher, and ServerE, a subscriber
In order to create a Digital Network, you would join ServerA, ServerB and ServerD together to form the network. Note the following:
•On ServerA, you would need to add the IP addresses of both ServerC and ServerE (the two subscriber servers) to the IP access list so that ServerA can communicate with either subscriber server if it has Primary status.
•On ServerB (the cluster 1 publisher), you would add the IP address of ServerE (the cluster 2 subscriber) to the IP access list; and on ServerD (the cluster 2 publisher), you would add the IP address of ServerC (the cluster 1 subscriber) to the IP access list.
To Configure SMTP Access for Cluster Subscriber Servers
Step 1 On a network location, in Cisco Unity Connection Administration, expand System Settings > SMTP Configuration, then click Server.
Step 2 On the Edit menu, click Search IP Address Access List.
Step 3 Click Add New.
Step 4 On the New Access IP Address page, enter the IP address of a cluster subscriber server at another location on the network.
Note Do not enter the IP address of the subscriber server on the publisher server that it is paired with.
Step 5 Click Save.
Step 6 On the Access IP Address page, check the Allow Connection check box.
Step 7 Click Save.
Step 8 Repeat Step 2 through Step 7 for each additional subscriber server on the network (other than the subscriber server that is paired with the server you are configuring).
Step 9 Repeat Step 1 through Step 8 on each network location.
Cheers!
Rob
