Not by pushing buttons.
I suppose the conversion parts exist since I assume European Wees measure in km, but changing the speedometer head to show a different odometer reading has title consequences in most states (assuming you are in the US). Don't know what Canadian Wees show. Probably km.
I don't know if there is a hardware mod to do it, or if it's done in software (firmware) that you can't get at. I suspect the latter. Maybe a dealer can reprogram it??
If you can't multiply by 1.61 I suppose you could add a second speedometer/odometer which can be switched to a km readout, like the Trail Tech Vapor or even a "bicycle computer".
1990 Kawasaki Ninja 250 (Rebuilt)
2011 Suzuki DL650A