My question involves name change laws in the State of: Tennessee

My son is about to be 9 years old. I've been with my husband for almost 8 years and married for 6 years next month. I don't know who my son's biological father is but I know who's been his father since he was 6mths old. The guy I thought was his dad was tested and turned out it wasn't his son either. Anyway, a few months ago my son asked me to change his name to his "Dad's" (my husband) and my husband asked me what can we do to change it as well. So I'm here asking what can I do to change our son's last name to my husband's last name legally? I don't want to pay a huge amount of money for this to happen.



Help me!