&nbsp;&nbsp;&nbsp;&nbsp;</td><td valign="baseline"> A <code>standard-object</code> <a href="ref-glossary.html#gl:instances">instance</a>
</td></tr></table>
</p>
<p><span class="fndoclabel">Returns</span> <br />The destructively modified <var>instance</var>.
</p>
<p><span class="fndoclabel">Events</span> <br /><a name="id1">If</a> <var>instance</var> is a <a href="ref-glossary.html#id256">unit&nbsp;instance</a>, a
<nobr><code>change-instance-class-event</code></nobr> is signaled at the start of the
class-cha