I have two girls, and they have not had any contact with their dad in 12 years. We have made several attempts to find him with no results. Is this not considered child abandonment. If so, how can I adopt them, or how can they change their last name on their own. Thank you

Ok, I will assume you are a step parent that wishes to adopt your spouses children?

You hire an attorney, attempt to serve the ex and then go ahead with the court action