<p>It depends... If it is a short answer about some basic topic and you wouldn't cry after it, it may be a good idea to delete it. However if you made some effort for answering the question (and sometimes got upvoted for it!) than it may be better to leave it because it still can be helpful. Recall when you search the site, the search results refer to both questions and answers -- in the future someone may be searching for your <em>answer</em>.</p>

<p>What you could do is alternatively:</p>

<ol>
<li>rephrase it, so it fits to the question as it was initially understood by you and to the true question (not always possible),</li>
<li>add lead, as proposed by <em>@gung</em>, that describes as you understood the question,</li>
<li>break your answer into two paragraphs with "old" and "new" answer, with some description of why the question can be understood in different ways, so it could lead to different answers (mixed strategy with 2),</li>
<li>add another answer that answers "the" question, with providing the lead to the initial one (mixed strategy with 2).</li>
</ol>

<p>So leave what could be helpful, but make sure that your answer is not misleading (by re-phrasing or providing a new one).</p>
