The first time, I went to a Kia service department and asked the clerk to do it. However, as I was already at something like 8,000km, by changing the interval to 12,000km, the reminder would come at 20,000km, which would have put my out of sync with Kia's recommendation. The clerk did tell me how to change it myself, but I don't recall the steps now. I suspect if you scroll through the menus it'll appear, or simply stop at a Kia service dept.