Fam. Code, § 17400.5

If an obligor has an ongoing child support order being enforced by a local child support agency pursuant to Title IV-D of the Social Security Act and the obligor is disabled, meets the SSI resource test, and is receiving Supplemental Security Income/State Supplemental Payments (SSI/SSP) or, but for excess income as described in Section 416.1100 et seq. of Part 416 of Title 20 of the Code of Federal Regulations, would be eligible to receive as SSI/SSP, pursuant to Section 12200 of the Welfare and Institutions Code, and the obligor has supplied the local child support agency with proof of eligibility for, and, if applicable, receipt of, SSI/SSP or Social Security Disability Insurance benefits, then the local child support agency shall prepare and file a motion to modify the support obligation within 30 days of receipt of verification from the noncustodial parent or any other source of the receipt of SSI/SSP or Social Security Disability Insurance benefits. The local child support agency shall serve the motion on both the noncustodial parent and custodial person and any modification of the support order entered pursuant to the motion shall be effective as provided in Section 3653 of the Family Code.