<p>If you have a good answer to a question that's no longer there, it would be a great pity to leave things as they are, rather than have the benefit of your effort available to be easily found.</p>

<p>This is a problem that does come up a fair bit; generally once a good answer to a decent question that was posted appears, the poster should normally do no more than "clean up" the question (small edits); unless the answerer completely misunderstood the original question, the answered question should left asking whatever it was asking before.</p>

<p>There's a number of possibilities here:</p>

<ol>
<li><p>If nobody has yet answered the current version of the question, it can be rolled back (you can do it or you could flag it I guess). The OP can then ask a new question if they want to ask something different. </p></li>
<li><p>If that's not suitable for some reason, you should feel absolutely free to post the old version of the question from the edit history as a new question (you must, however, credit its author and you should link to the original post). </p></li>
<li><p>You could write an entirely new question to which your previous answer is an answer; in some cases this may be a better choice.</p></li>
</ol>
