I gave him free rein to do what he needs to.
If we could convince him to give you free rein to helping us with him remaining totally in the dark, we'd both have what we want.
If you gave me free rein I'd have every kind of animal there was.
Given free rein to improvise as he saw fit, the law student had found the employee and created his own sting.
When he realized the strength of the national reaction, he allowed the patriotic fascisti free rein to reestablish order and practically exercise many functions of Government, while he assumed an attitude of Olympic calm and posed as being au dessus de la melee, so as to avoid compromising himself with any party.