Shock treatment. Barely heat it, not so it’s hot to the touch, but warm and pliable. Then flatten the fuck out of it with something cold. I have aluminum plates for this but you could use some steel that fits in the freezer, or steel with a bag of ice on it. The idea is that we get it pliable, put it how we want it, and then cool it off rapidly to make it stay like that.

Alternate: tell the boss to get a decent walk off mat