A turbine vane includes an airfoil body having a leading edge, a trailing edge and a smooth outer surface. A cutout is included within at least one of the leading edge and the trailing edge, the cutout removing a predetermined area of the airfoil body. A coupon is coupled in the cutout to replace the predetermined area of the airfoil body. The coupon includes a first corrugated surface on at least a portion of an outer surface thereof. The coupon allows for the addition of advantageous wake mixing and cooling efficiencies to preexisting vanes.