"./vomadm host-mgmt -remove -host"  fails

Removing host
Failed to remove host : Cannot remove host. It is configured as a Control Host
 

There's a patch for 4.1 that allows to use the --force option to remove a host that is configured as Control host:
https://sort.Veritas.com/patch/detail/6040

Please install the above patch.  Once installed, you should be able to do:
Execute the below command
  $ ./vomadm host-mgmt -remove -host    --force
Execution of above command will remove the MH from the VOM UI