Suppose I make a question but someone gives me an answer that points me that that wasn't actually what I wanted to ask. Sometimes I'm a little confused and the ultimate question I want to make isn't immediately clear. Can I ask it and change it as I develop a better question or should I make a new question?
In general, it is considered poor practice to change a question drastically enough after an answer has been given. The person could have spent quite some time writing up a good answer, and if an edit invalidates it, that effort can be wasted. In this case, the effort clearly would not have been wasted - it would have helped you overcome part of your problem - but it now doesn't answer the entire question.
In some cases, this can risk inadvertently turning into a chameleon question, which is incredibly frustrating for answerers. It could also turn out that you've fallen victim to the XY problem, where you ask about Y, but deep down, you really wanted to know about X. In both cases, it's better to start anew, for a few reasons:
- It's less frustrating for answerers.
- You get a clean slate, where you can better clarify what you do and don't know.
- Folks who've already answered don't have to edit their answers or risk them being invalidated.
When do write up the new question, though, do be sure to refer back to the first question, including a link. Also, if you can briefly describe what part of the problem that question solved for you, and how you're asking about something different, that can make things clearer for readers.
A question should not be a moving target.
If your question gets answered, and this answer makes you realize you actually wanted to ask something else, then ask a new question. Do not edit the original question making the original answer incomplete or even wrong.
However, if the point was just raised in a comment it can be better to edit. Say, a user comments "The answer to your Q is A. But actually you may mean to ask Q' which is more interesting, natural, etc." then usually the point of that users action was precisely to induce a clarifying edit, and you should do just that.