Official comment
NO!
Not only do you need to deactivate it, but you also need to ask us to unlink it from your account!
If you activated a rekordbox license to your PDJ account and then you sell the license, the next owner can't activate it because that license is still tied to your account, even if it's not installed on any computers.
You need to file an inquiry ticket here and our rekordbox support team will be able to gather some additional information to release the license.