You can sell your ticket or give it to someone else any time. Please also note that it is up to you and the new recipient to work out your own payment method. A ticket is only valid for one person and can't be shared. On arrival at the accreditation, you'll get a wristband in exchange of your ticket which you need to keep on your wrist for the whole event.
You don't need to tell us that your ticket has a new owner, as we'll have name badges where attendees fill in their names by themselves.