Once you have applied mocap data to the face, you can key offsets on top of this data to adjust it. The offset is carried through to the mocap data.
To add offsets to the mocap data
Select some animation controls and move them to where you want.
Plot the animation to bake the mocap data and the offset animation into fcurves (see Plotting (Baking) the Mocap and Keyframe Data).
See also Adding Offsets to Mocap Data [Character Animation] for more information on different methods for adding offsets.