in park, ignition on, engine running or not, set steering wheel, wing mirrors, seat position, seat belt height, and headrest position. hold down 'SET' and also press '1' and hold it briefly until you hear the tone.
then put the other driver in the seat, and re-set wheel, seats, mirrors, etc., then hold down 'SET' and press '2' as above.
then get back into the seat and press '1', and eveything should go back to your chosen positions. (on mine, the driver mirror goes skywards, so i wait til the other settings have finished adjusting, then stab the mirror adjust button, which stops the mirror, then i reset the mirror position, but as the car's 14 years old, i haven't tried too hard to find the little glitch!)
hope this helps.