How do you restart a Nintendo DS Lite

I'm not sure how to reset it, but you can change data whenever you want to.
How To Change Data On Your Nintendo DS
1. Make sure your DS has no game cards in it
2. Turn the DS on
3. On the menu, tap the small Nintendo icon at the bottom screen (it's near the middle at the bottom)
4. Tap the icon that you want to change (you can change the time, your name, bithday, favourite colour, date, etc. by pressing a certain icon)
5. REMEMBER TO SAVE ALL THE CHANGED DATA (after you've changed something, go BACK and it will say something like "saving data please wait")
and there you go :)
By the way, if you meant to reset the data on a certain game, there are different ways of reseting the game depending on the game. :)))))