Legal Question in Family Law in Louisiana

Re: how to change my grandaughters last name to her fathers

Changing the name is very simple, but her father will not be her REAL "legal" father until his name is put on the birth certificate. So, I would suggest an Intrafamily Adoption. That is, the husband of your granddaughter's mother adopts your granddaughter. That way, when a judgment is rendered, he will be declared her dad and her new birth certificate will show the new last name and your daughter as the mother and her dad as the dad. It is more simple than this answer.

Re: how to change my grandaughters last name to her fathers

No need to do an adoption, as the marriage of the natural parents automatically legitimates the child. We use the simple affidavit available at the health units or Vital Statistics in New Orleans, which when executed by the father & mother before a notary public and two witness, once filed with Vital Statistics will change the child's last name to the father's which will be put on the new birth certificate along with the father's name as the father.