If a party wishes to modify the current child support order and one of the above situations exist, then that party will file a Petition for Modification of Child Support and Judgment of Arrears ("Petition"). The person filing the Petition is the "Petitioner" regardless of whether he/she was the Plaintiff or the Defendant when the child support order was first entered. The other party is referred to as the "Respondent."
Once a Petition has been filed, a copy must be formally given to (also called served on) the Respondent, who is then expected to respond the Petition. Personal service of the Petition and Summons on the Respondent by a Sheriff is required for the Petition UNLESS the Respondent completes an Acknowledgment and Acceptance of Service form. Formal service is required for the Petition so the Court has proof that the Respondent actually received the papers. Other forms of service exist, but these are the easiest methods that meet the formal service requirement for a Petition.