Keep your account for future use, or have it deleted by Control4 if not.
If you want Contol4 in any new place, that HE license is good for life, but you must keep the same account.
As for what to give the new owner, a dealer will have to register the system, so I would unregister it from your account after logging out of all the personal streaming services.
No info is required to transfer from the old owner to the new owner. The dealer can register the system to a new account as long as the system is unregistered.
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