C.R.S. § 14-5-506

(a) An obligor may contest the validity or enforcement of an income-withholding order issued in another state and received directly by an employer in this state by registering the order in a tribunal of this state and filing a contest to that order as provided in part 6 of this article, or otherwise contesting the order in the same manner as if the order had been issued by a tribunal of this state. (b) The obligor shall give notice of the contest to: (1) A support enforcement agency providing services to the obligee; (2) Each employer that has directly received an income-withholding order relating to the obligor; and (3) The person designated to receive payments in the income-withholding order or if no person is designated, to the obligee.