You can get a refund, usually, at the box office. Because tickets are in high demand, they will most likely take them back to be sold as cancellation line tickets.
Or you could try to sell them outside the theater for the price you bought them for. I'm sure there are many theatergoers who would buy them, again because Wicked tickets are highly demanded.
"We like to snark around here. Sometimes we actually talk about theater...but we try not to let that get in our way." - dramamama611