When using the smc -cloudmanaged command to move Symantec Endpoint Security devices to a different ICDm it completes without error message and the clients do not move.
A password is set in the System Policy.
Symantec Endpoint Security where a password is configured in the Client Password Settings of the System Policy.
There are two options to workaround this issue:
1) A password is required so the command needs to include -p password
smc -p password -cloudmanaged \path\to\package.exe
2) The password can be removed temporarily from the System Policy until all devices are moved to the new domain.