Stupid question: how do I do a line edit?

There are times a story gets ruined because the AI gets a name, time, or gender wrong. The most egregious is when it's like: "Fernando gasped. CBT. He was, as the user's trope specified, becoming a dragon from having Meredith smash his testicles," but there are subtler issues and I've seen people discuss changing the text, but I can't find that?