This is the official line
“Away tickets are non-transferable, away tickets are issued for the Holder's sole use, and you shall not sell, dispose of, assign, transfer, lend or otherwise deal with the away ticket or benefit of the same to any other person without the prior written consent of the Club. If the ticket is resold or transferred without the prior written consent of the Club, it will become void, and the Holder will be refused entry to or ejected from the Grounds for that Match or any subsequent Matches. A transfer may be authorised by the Club in the Club's absolute discretion and providing that such sale or transfer is in respect of an individual Match and in consideration of no payment or benefit in excess of the face value of a Match Ticket. Such re-sell or transfer will be subject to these Terms and Conditions.“