If you have to reschedule a date, should you worry that she'll be too busy? How should you go about ensuring that she'll still reschedule?

Example: First date went great, K-closed and cuddled. Set up 2nd date after some long prodding and her saying she was busy, but I may have to reschedule. I ended up trying to flip the script on her and said "We can play it by ear. Worst case scenario, I flake on you" Thoughts?