A party or support enforcement agency seeking to modify, or to modify and enforce, a foreign child-support order not under the Convention may register that order in this state under Sections 5700.601 through 5700.608 if the order has not been registered. A petition for modification may be filed at the same time as a request for registration, or at another time. The petition must specify the grounds for modification.
Source:
Section 5700.616, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=FAM§ionNum=5700.616..