Changing owner of HC2

Hello, Changing owner of HC2, and grouping the HC2 central in an existing account.
I need to include a second-hand HC2 central (bought to his previous owner) in my account. When I try to include it in my current account, I get a message about the HC2 central cannot be included because it is in another account. How can do it? I have made a reset (pushing reset button for 6 seconds), but the same message appears.