Okay finally got some practice in before shooting light faded and then found a small sauce pan. I heated the water on an electric range until it was pretty warm to the touch. Placed the horn in the water and let it come up to a good boil. Stirred occasionally to make sure the horn didn't stick to the bottom of the pan (my Mrs. idea!)
I didn't set a timer but the horn was stirred around for approximately 10 minutes. Then I took the thinner of the two pieces out and set a large glass measuring cup-thingy filled with water on top of it while sitting on the flat counter.
I noticed that the horn was soft enough to bend but I must not have had enough weight sitting on it because when I lifted the weight off it sprang back up to the original shape. Or I took off the weight before it had time to cool all the way down. So I placed it back in the boiling water and took out the thicker piece.
This time I held down on the measuring cup thingy until I thought it was cool enough to touch. This worked much better as it stayed flat. Then proceeded to do the same thing with the thinner piece.
If I can figure out how to add my before and after pictures I will, but for now you'll have to take my word on it.