New regulations adopted in 2016 provide that a discriminatory housing practice includes "[f]ailing to take prompt action to correct and end a discriminatory housing practice by a third-party, where the person knew or should have known of the discriminatory conduct and had the power to correct it." 24 C.F.R. §100.7(a)(iii), 81 Fed. Reg. 63074, Sept. 14, 2016.