If you are selling secondhand you may delete the hardware serial from your SSL account.
If you have purchased second-hand you may contact the seller to transfer SSL plugin iLok licences to your iLok User ID directly and pay iLok's transfer fee. Here are iLok transfer instructions.
Please note 4K B and Meter bundled with hardware are non-transferrable.
Additional bundled software, such as the Production Pack, is non-transferable and available to the original owner only.
SSL is not able to transfer software for secondhand units nor revoke any activated iLok licences.
Regarding UC1 please see Secondhand UC1.