Is it possible to change the UIM Domain after installation?
This is not supported.
Domain changes post-install are not tested by QA for the amount of possible failures that could permeate the UIM environment.
Changing the domain on UIM would have far-reaching consequences, including the loss of all users (because hub/login security is tied to the domain), and would necessitate rebuilding all the tunnels and queues, and there are also many unknown factors because Broadcom/CA has never developed or tested any process for changing the UIM Domain Name since it is not supported.
The UIM Domain should be considered permanent and should be carefully chosen at installation time.