Set your Travel Sentry lock to the current combination.
Pull the shackle--the curved steel piece that hooks through luggage zipper holes--straight up to unlock the lock.
Turn the shackle 90 degrees counterclockwise so the entry notch is hanging over one side of the lock. Press the shackle down firmly and twist it another 90 degrees counterclockwise. Hold the shackle in this position.
Pick a new combination and enter it on the dials.
Pull the shackle straight up turn it 180 degrees clockwise to line up the entry notch with the hole. Push the shackle into the hole, as you would to lock the device. Turn the dials away from your new combination. Pull up on the shackle. It will not release if you have performed the reset correctly.