Help - Wrong Surname

Hi there.

I know I posted the same on the introduce folder but maybe here there's more people reading it.
I use to help friends to find the cheaper way to fly to their destinations. Often family, colleagues and friends come to me to help them.
This time I need help. I've made a big mistake.
I've booked two tickets for a couple. Since they are married I've booked it with the same surname. I was wrong. One ticket as the wrong surname. And worst, I've made the check in. The flight is on Friday of the next week, and I know that any charge will be at my expense. I'm done. Is Easter time. The prices are rising every day.
The ID's are correct. The ID number is the same. Any chance of solving it without have to paying for a all new ticket?

Help Appreciated.
Thank you.