Ajax and reusing/removing instances

I couldn't find something about it in the forum, tho I guess it should be a quite common problem.

I'm using ckeditor 3.2 inside an Ajax snippet. After reloading the snippet, I get a Javascript error "The instance xxx already exists". I tried to remove the instance, but it didn't work:

if (CKEDITOR.instances.myText != null) {
  CKEDITOR.remove('myText');
}
CKEDITOR.replace('myText');

Any idea how this should be done?

Thanks in advance,
Roman