Question for you: 

I have an 'established' employee who feels that she is 'beneath' reporting to a younger manager (who happens to not only have 12+ years experience but also has the sharpest learning curve and within 6 weeks has proposed and implemented three significant improvements). Unfortunately, due to a reorg (I just got promoted to another line of business, which necessitates this change), this change is not an option.

How have you overcome 'ageism' and attitude successfully?