If it's a US spec bike, it will change over, but if it is a euro spec bike, you'll need to get a different speedo. Push the button... if that doesn't change it, you'll need a different speedo. With any luck you can get someone to trade even if they need the KM side. I know there have been a few trades here already.
I have the correct speedo kmh but with HRC wiring harness km travelled are not added to speedo. Too hard to sell a bike which says only travelled 2km as a street bike 4 years old, so thats why trying to get speedo with realistic kms.