Undo bolt on the side of the transmission. Possibly a 17" or 19" bolt IIRC and its kind of adjacent to and slightly to the rear of the engine sump. This will allow for partial fluid drainage. Refill via the dipstick tube. Refer to the owners manual on how to check the fluid level.
A full change can apparently be done by disconnecting an autobox cooler hose and with the engine running, replenishing the fluid at the same time - but check into/do a search on this site first - there's someone on here that's done it this way.