What if Your Coworker Regularly Goes Off the Ranch and Doesn’t Use Change Control?
Don’t cover for them.
Ask them about it first to make sure there wasn’t an emergency change request you’re unaware of for the change, but be honest about what happened when you’re asked.
In other words, treat them as an equal and a grown-up.
Sometimes in this situation, people sugar coat things or cover for the person who makes mistakes. You need to treat them as an adult though.
If you made mistakes, you would own up to what happened and work to not do it again, right? It’s just about respectfully allowing others to own their actions.
Kendra’s answer is a good mixture of technical explanation and not being socially inept. It’s important to follow that two-pronged approach.