Iowa Code § 630.16: Equitable proceedings.

At any time after the rendition of a judgment, an action by equitable proceedings may be brought to subject any property, money, rights, credits, or interest therein belonging to the defendant to the satisfaction of such judgment. In such action, persons indebted to the judgment debtor, or holding any property or money in which such debtor has any interest, or the evidences of securities for the same, may be made defendants.