Grip, schmip..... Doesn't matter.
All that matters is how the speed is taken off, WHILE BEING DECEPTIVE!!!
Use your fast or drop ball grip, then instead of palm up at 9:00, get to palm down. A good verbal que is to say "thumb on the hip"
We want some form of brush on every pitch... (The upper thumb area close to the wrist brushes the thigh on a CU)
And finish the pitch Palm down JUST LIKE THE FAST OR DROP!! This will force a bit of a pushing motion with fingers beside the ball rather than behind it. She'll have effectively removed all whip and IR snap... BOOM, awesome change up
Again, it's gotta look the same to the naked eye.