Procedure to register child support order of another

state for modification. A party or support enforcement agency seeking to modify, or to modify and enforce, a child support order issued in another state shall register that order in this state in the same manner provided in Sections 601-601 through 601-608 of this article 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.