This answer has just been expanded a lot by a different user. It went from a single sentence to a 4 paragraph answer! More than 90% of the answer were not written by the author.
Is it appropriate to make such large modifications to an existing answer when you are not the author? Would it not be better to write a new answer yourself?
I don't think it's appropriate to make large modifications.
The Help Center says:
Some common reasons to edit are:
- to fix grammatical or spelling mistakes
- to clarify the meaning of a post without changing it
- to correct minor mistakes or add addendums / updates as the post ages
- to add related resources or hyperlinks
Nothing about a rewrite, which is the case here. Leaving a comment as to why the post does not meet the quality standards so OP can expand (and learn!) is better.
Also the editor can submit a full answer as well.
P.S. Back when I joined the site, I made the mistake of a one-liner answer, and the votes and comments taught me how the site works. It did not drive me away. (Example for the 10k club.)
