FL Law on Child Last Name Change

What is the name of your state? Florida

My daughter is 14 years old. I was never married to her biological father, however I gave her his last name when she was born. He hasn't seen her in 10 years or so. I have no idea where he is now. My husband and I have been married 11 years. My question is how do I go about changing my daughter's last name?

http://www.ilrg.com/forms
go down to name change

I am not a lawyer. good luck!