I have done some research about it.
It really depends on the lic file in “C:\ProgramData\McNeel\Rhinoceros\6.0\License Manager\Licenses”. If you use Zoo license server, you can copy the file from another PC and it works. At least for me 
If you by chance have old server name in registry key \HKEY_CURRENT_USER\Software\McNeel\Rhinoceros\6.0\License Manager , it prompts you for new address of the Zoo server. If there is no server key at that place in registry, it uses the right Zoo server from registry key \HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\McNeel\Rhinoceros\6.0\License Manager .
But you need the lic file to have at the right place.