This is the most frequently asked question. I must admit that I'm far from a service interval so I have not tried myself, but here is the link to the online smart car encyclopedia
Go to the evilution websight and watch the video and follow the instructions. Remember to have the left button depressed when you turn the key back on. Keep holding it down and you will see 10k come up and then it is reset. Good luck. It takes a bit of practice.