1. From the graphic editing window open mini menu and
deselect "off velocities" in view filter.

2. Click Drag the selection box over the controller data
(in this example velocities) to be edited.

3. Click on "reshape box", and don't hold down option key

4. Click and drag crosshair to get the desired shape.

5. Play track to check results and if the results are not
to your likeing, use the "undo" feature, and try again.