I believe that most people want to do the right thing. Every day I encounter countless people who are taking care of one another in positive ways. Yet, no matter how well meaning or hard working we are, people make mistakes We can't see all perspectives, we don't walk in all shoes, and we are imperfect people. So with humility we have to accept the fact that we'll make mistakes in life, and with good intentions we have to speak up when mistakes happen so others don't encounter the pain, suffering, or problems those mistakes cause.
Identify the error
Take some time to think about the error. It may be a good idea to describe the error in writing.
Politely communicate the error
When a dangerous error is made, it can be difficult to be calm or polite. This week when my loved one was painfully suffering after an error made in the emergency room, I was very upset and probably not as polite as I could be. As much as possible we need to be polite when explaining an error, and if someone explains an error to us in an upset way, we need to listen and acknowledge their pain. Yet, obviously if the person is enraged or dangerous, we need to get away and get help.
Advocate for change
If the error you've encountered is a systematic error, it's good to advocate for systematic change. Sometimes errors have less to do with individuals and more to do with how a system is run. Sometimes systems set people up for error and this is not good.
Legal action
In general, I'm not a big fan of legal action when it comes to error. I remember once at the school where I worked a parent took out a law suit due to an accident that happened in the school hall. I thought that was an extreme and costly reaction to a relatively common mishap, yet the legal suit did lead to a change in practice that protected people from a similar mishap going forward. A friend of mine's doctor relied on a high school aid to perform a serious medical procedure which resulted in a long term injury for my friend. That was clear negligence on behalf of the doctor. My friend thought it was strange at the time, and in hindsight, wish she had spoken up. After extensive therapy, my friend's issue was mostly resolved. It was the end of the doctor's good career, and my friend chose not to litigate as she didn't want to ruin what had been a good career overall. Legal action takes time and money, but when it comes to serious errors, legal action can remedy serious errors that occur and help those who faced the terrible problem have the money they need to survive in positive ways.
Advocacy groups
As I've learned it's hard to make change on your own, and it's much easier to make change when you work with advocacy groups. When possible, it's good to join advocacy groups to make the kind of change that improves lives.