Suppose I answer a question based on my limited knowledge of that topic (which I know that I should not do, but just assume that somehow stupidly I do it.)
Later I research about the topic and realize that the answer is completely different. In this case, can I change my answer? And I am not talking about just making edits but completely changing the answer.
Completely changing its meaning, I think, would definitely call for posting a second answer.
Even though people can change their votes after an edit, most of them are unlikely to go back and do so since you don't get a notification for that. Votes would then be pretty much based on the old version of the answer, and not reflect its current state. Pretty dishonest, I'd say, especially if that answer was already accepted.
On the other hand, a complete rewrite while keeping the answer's original intent/meaning, I'd be fine with since the votes should still apply.
Stack exchange encourages continuous improvement. If you can make your answer better and you have the time and inclination to do so then you should make your answer better.
Deleting your answer or making it obvious that your answer used to be different shouldn't be necessary. Future voting should be based on whether your answer is useful now, not how useful it was in the past.
Of course, if your original answer has been voted down, you may find it difficult to persuade people to vote it up in the future, so deleting and writing a new answer may be a better option. Writing a new answer without deleting your other answer could leave you in the situation where the answer you know is better is languishing at the bottom of the page, while your admittedly worse answer is ranked more highly.
Overall, I think it is better to just make your answers to be the best they can be, and not worry about what others think about your earlier attempts.
Future voting should be based on whether your answer is useful now, not how useful it was in the past What about current or existing votes? People don't go around updating their votes when a post is updated.
– Möoz
Nov 13 '17 at 23:55
A third option to other two (that I frequently use) is to EDIT IN the new answer (as "UPDATE) and leave the old answer below as "OLD ANSWER" - in the same post. This in my opinion combines the benefits of both approaches - you keep the old content (that you already got upvotes for, so you're not "cheating" previous upvoters by removing that content and replacing with another); AND you're not creating a fully separate answer which makes little sense to me as it's still your work. I don't see it as a significantly better approach to creating a new answer, but personally I prefer it to the latter.
Sure you can. Alternatively, you could just make a new answer to the question, which might be more appropriate in some circumstances. I've done the latter occasionally, and that's probably the preferred method in most cases.
I think if you have answered a question, and you later come to believe that your answer was wrong, the sensible thing to do is delete the original answer, since on the whole, wrong answers decrease the usefulness of the question to others. If it's a matter of debate, then a short paragraph at the end explaining why you no longer agree with the answer might be appropriate instead.
New and better answers should always be in a separate post, in my opinion.
