Leigh Branham writes in The 7 Hidden Reasons Employees Leave,

There are times during an exit interview when it may become obvious that an employee who has decided to leave is really heartbroken at the prospect of leaving, but feels there is no alternative. For example, an employee may love the job, the work environment, and the colleagues, but has decided to leave because the boss would not grant flexible hours. In these situations, an alert and proactive exit interviewer may be able to intervene to help change the boss’s mind or report the situation to higher ups who may be able to assign the individual to a different manager.

In her book, HR from the Heart, Libby Sartain, senior vice president of human resources at Yahoo! Inc., recommends always asking departing employees, “Is there anything we could have done to keep you here?” You may discover that there may still be a sliver of a chance to keep valued talent and save the company money in avoided turnover costs.

Sartain also recommends trying to connect with departing employees on a deeper, more human level by asking such questions as:

• If you had the last three months to live over again, what do you think you would do differently?
• What have you learned that you can take with you to your next job?
• What are you proud of from your time here?
• What goals did you meet?
• What accomplishments will you be able to take with you?