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 as provided in sections 25-1301, 25-1302, 25-1303, 25-1304, 25-1305, 25-1306, 25-1307 and 25-1308 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 shall specify the grounds for modification.