What does it mean to serve someone with an original notice when it comes to changing my 5 year olds last name?

Original Notice is a form signed by the clerk of court to inform interested parties that a lawsuit has been filed and to request an Answer back from those parties.  The Original Notice must then be served upon the interested parties and the service filed with the clerk of court.  This is a system to ensure that all potential parties to a lawsuit have been notified and properly served to bring them within jurisdiction of the court. In this case, I would assume that the son's father or mother is the party who must be notified, as they would have an interest in their child's case.  Contact your attorney and discuss the case with him/her as to who should be served with Original Notice.