If any of you followed the procedures listed here, http://www.cisco.com/en/US/customer/products/sw/voicesw/ps2237/products_maintenance_guide_chapter09186a008044380f.html#wp1100939
I can tell you this will work ... until - your original partner server is shutdown. Unity will get many AV_Wm errors in the application event log. Messages will queue up in UMR. Here is what I did to correct, making sure I backed up Unity beforehand:
1. At this point, the Unity_servername account/mailbox Exchange properties will show the mailbox on the new partner server. The problem is the Unity_servername entry in the SQL database will show the old HOME server, the one that was shutdown.
2. Delete Unity_servername from Active Directory
3. Run ESM Mailbox Cleanup Agent
4. Delete mailbox
Note: If you do not do these steps, Messagestore config wizard will abnormally terminate with Dr. Watson error (at least it did on my Win2K3 server)
5. From SQL Enterprise Manager, delete the line that contains the Unity_servername from the database. Contact TAC beforehand if you do not feel comfortable doing this on your own.
6. From Control panel, add/remove Programs, click on the Change/Remove Message Store Configuration
7. Follow thru with all of the steps as referenced in this link - http://www.cisco.com/en/US/customer/products/sw/voicesw/ps2237/products_upgrade_guides_chapter09186a0080205a7f.html#wp1126324
Works great! I also found this updated Unity 4.2(1) link that discusses the incorrect procedures - http://www.cisco.com/en/US/customer/products/sw/voicesw/ps2237/products_administration_guide_chapter09186a008061c380.html#wp1055479
However, in may case the mailbox moved OK and all was fine UNTIL the partner server listed in the UnityDB database for Unity_servername was shutdown.