how to change "price" and "location" when editing a thread...

I posted a thread for my Continental a few months ago in the "cars for sale" section of the cl***ifieds. I went to edit the ad a couple days ago to drop the price, but it still says the old price on the header for the ad. I looked and looked but can't find any way to change that "price" section or the "location" section for that matter. Any help would be greatly appreciated. Thanks.