You need proof of citizenship.
Did you previously report child's U.S. citizenship?
No, I have not reported child's U.S. citizenship to you.
Does it cost anything to replace my child's card?
To replace you child's Social Security it is free if it is lost or stolen.  However, you may not need to replace card yet if you know the social security number.
What proof do I need to show my identity at Social Security?
We must see your driver's license or state issued no-driver card.
What happens if I do not have one of these documents or cannot get replacement within ten days?
We will ask for other documents that are current and they need to show your name, date of birth or age and preferably a recent photograph.
Do I really need to replace my child's card?