Change Skin after Load?

Hello, I'm trying to change the skin after the editor has loaded via JavaScript. I'm trying things such as:

CKEDITOR.instances.SomeId.config.skin = 'theme';

but that doesn't seem to work. If I try to replace the object via CKEDITOR.replace I get an error letting me know that the object has already been loaded.

Is there some way to change config options such as the skin after the instance has shown, if not, is there some way to re-replace the instance without destroying it? I don't see anything in the API.