Have a ticket but can't make it. How do I give it to my friend?

I got 2 tickets for the doubles quarter final on Saturday through newmarket holidays. Unfortunately, I won't be able to fly into the UK for the game since my wife fell sick. I was planning to go with my nephew and his ticket was in his name so he should be fine. However, since my ticket is now available, I'd like to give it to his friend who is also in London this week so they can go together. But since it's in my name I don't know how to go about this. Any ideas?