tedster - 8:02 am on Nov 16, 2011 (gmt 0)
There was no special method offered for giving that feedback, at least as far as I heard. I'd say the Google Webmaster Forum is the place to go, or maybe a Reconsideration Request.
However, note that Matt was talking about using this input to improve the algorithm. That's not the same as a manual review of your site that could lift the Panda verdict.