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

Hello,

I have a 5 year old daughter with a woman, we all live together in my house. We were never married. Paternity is established, I am on the birth certificate as the father. I am allowing the woman to live at my house only for the good of the child; we do not get along well.

Mom recently signed up for the PTA, and when the welcome package came from them, it had on the address label: "to the mother of Childfirstname Fathersurname Mothersurname." (There is a space on the sign-up form for the parent to enter the child's name, and I presume this is what child's mother put on the form.)

Needless to say, I was dumbfounded. THe child's last name (mine) had now been relegated to a middle name, and the mother's surname was listed as the child's surname. Now, I know this is only a PTA application, but can the mother continue to do such things, presuming this is what she did? What steps should I take? Thank you.