The father of two children filed a petition seeking a modification of his child support obligation almost two years after one of his sons emancipated, contending that his support obligation should have been retroactively modified to the date of emancipation. The trial court found that the support obligation could not be retroactively modified earlier than the date of filing the petition for modification when there are remaining unemancipated children subject to the support order. The court of appeals affirmed, applying the plain language of A.R.S. §§ 25-327(A), -503(E), and Guideline § 25 (if “the duty to support one of the children stops, the order is not automatically reduced by that child’s share”). The court distinguished this case from Guzman v. Guzman, 175 Ariz. 183, 184, 854 P.2d 1169, 1170 (App. 1993) on the grounds that only one child was subject to the support order in that case. Thus, the court concluded, while the Father’s obligation to support the son automatically terminated upon the son’s emancipation, the support obligation did not automatically decrease in light of the father’s continuing duty to support his other child.