can you reverse an adoption by stepparent?

Given that your biological father is deceased, I believe that changing your last name is the best you will be able to get accomplished. It sounds like you truly want to "reverse" the adoption and I don't think that is possible, but you may want to check with an attorney in your area, as laws are different in each state. You said you haven't spoken to your adoptive father in some time, but I'm curious, is it more than that? I'm being nosey and you do not have to answer that if you do not want to, I'm just curious.