I agree with other posters - don't talk about failing to gain your goal of pharmacy admission.
What they are looking for with this question is your ability to adapt your approach to a situation when it has proven not to work for you. They want to see if you're flexible & willing and able to change when its required.
In actual practice...this happens everyday. In the retail setting, you might explain a new medication to a patient, but she's not understanding. So...you have to change your approach. Saying the same thing again the same way won't increase understanding.
In a hospital setting, what works for Zpack's institution might not work for mine. We might accomplish the same goal, but by using different methods. The reasoning could be varied....it might be due to physician mix, budgetary constraints, employee flexibility...whatever. But...in trying to obtain a particular goal - there are many ways to get there.
Now.....think about a situation which occured in your life. Was it a class you took in which you were very prepared for an exam, but failed it miserably? You might have used the methods which have always worked for you before, but for this class & at this time...it didn't work. Now...what did you do - study just like you did before, but harder? Thats not what they want to see. Did you change your method of study?
Your example might be from school, work, volunteering or an extracurricular thing you participate in. Have you ever had a situation in which you've had to change YOURSELF to try to accomplish a goal which was unattainable when a previous method failed.
Good luck!