A party or support enforcement agency seeking to modify, or to modify and enforce, a child support order issued in another state must register that order in this State in the same manner provided in sections 1601-1608 of this title if the order has not been registered. A petition for modification may be filed at the same time as a request for registration, or later. The pleading must specify the grounds for modification.
15B V.S.A. § 1609