This question already has an answer here:
I made an edit to my post while leaving the "explain the reason for your edit" part empty. But now I want to add the reason without re-editing the question. Is there a way for this?
Discussion : If not, should there be a way to do this? I think it might be nice, but I'm not sure if it would cause any bug or vulnerability or something.
Edit: Now I think and see one downside of this feature would be that it would require to save the previous edits, so maybe a little bit more database burden. However SE might already be saving them, with edit reviews and such. So it might not be a big deal at all. So I'm adding the "feature-request" tag to the question, also writing my edit reason :)