2003 Civic check engine light

[CRX-YEM]

Well, my wifes civic flashes the check engine light during start-up, whic hI believe is just a "go to the dealer please so we can make stuff up that needs to be repaired" light as it started doing it at about 15,000 miles. which is about the same milage as the maintanance schedule suggests do yada yada yada...

So how do I reset this light I know there's some way to do it

Thanks in advacne