If you heat it enought to work with it, you will destroy the shape. It will sag. I would make a plug and have one made. I have a vac former that I got last year for canopies. Havent used it yet but the guy I got it from pulle a bunch and they look good. I wouldn't try to heat the one you have and re-shape it witout some kind of plug. I am almost certain you will trash it.