How do i get tomtom to reculate routre - Tomtom One XL GPS Receiver

Turn the GPS on. Tap on the LOWER RIGHT square of the main screen. Then tap on the "FIND ALTERNATIVE ROUTE" button. One of the options should be "recalculate route"

By the way, a TomTom GPS will automatically recalculate the route if you make a wrong turn or if you go past a street you should have taken.