I get asked this question a lot when I do one-on-one sensitivity training sessions. These situations typically arise when a very valuable or very senior person (or both) engages in some kind of problematic behavior (e.g., inappropriate or unprofessional comments, bullying behavior, harassment). The employer wants to keep said employee but try to rehabilitate him or her. I typically meet with the individual for a number of hours and work through the problematic behavior, the legal implications, the other business consequences (e.g., reputational damage), and tools for change. Is this intensive form of training effective? Sometimes.
I’ve met with knucklehead senior executives who refuse to take any ownership of the issues the led them to me. Those ones generally are not in for much of a transformation. But even more often, I’ve worked with well-meaning folks who didn’t realize how detrimental their behavior was. While ignorance is not a defense to the law, it can be a state of mind amenable to education and change. So yes, I do think people can change. That doesn’t mean they necessarily will, but it does mean that when you have a valuable employee who needs some redirection, one-on-one training can be just the thing.