This Knowledge Base article outlines the procedure to change the Cluster Name in vCentre AZ configuration.
Operations manager
For the procedure you need to enable Advanced mode on OPS Manager, see How to Enable Advanced Mode in the Ops Manager and retrieve AZ GUID and backup AZ configuration in case you need to restore the original configuration.
As the procedure is not recommended, if it is absolutely necessary to do please open a support request with Broadcom support to review the issue.