Question: how do i legally change my child's last name in california?
Answer: Fill out your court forms. ... 
Have your forms reviewed. ... 
Make 3 copies of all your forms. ... 
File your forms with the court clerk. ... 
Serve the other parent of your child. ... 
Publish the Order to Show Cause for Change of Name (If Required) ... 
Go to your court hearing. ... 
Get your Decree Changing Name from the court.