Well, a doorway page is a page that exists only to link to or promote other pages. It offers no real value or content of its own for the visitor.
You know your site best, so put on your thinking cap. This message could have been triggered if the spider sees a page whose spiderable content looks like that. Such a page would not be integrated into the site navigation - it would only exist outside the structure and link in to your main pages.
If your rankings have not suffered I would have no concern for the message unless you can think of a page or pages on your site that fit the description I gave. If you do have pages like that, then either delete them or make them more useful for the visitor and integrate them more into the rest of the website.
As far as a reconsideration request - there's nothing to reconsider if your rankings have not been damaged.