Does anyone know an effective way to take a piece with body wave and make it more like a straight piece?

I purchased a product from Sally Beauty site. "Curl Remover" For tinted hair, it's milder and it worked very well for me. I followed the directions and was very pleased with the outcome. I am sure it is just a perm solution but rather than curl it, you comb is straght and again I was very happy with it. My natural hair is straight and I don't care at all for a body wave. If you have an old unit you can test it out.