A brilliant idea can get stopped in its tracks if it resembles something that didn't work in the past, John Kotter writes. That can be especially frustrating if a higher-up doesn't see how conditions have changed in the interim. What can you do when someone says 'it's been done'? First and foremost, don't try to argue about past events. Instead, focus on the present and try to find ways to assuage any lingering doubts or objections.