change distance to metric?

I'm assuming you are asking about a specific app or data field but you have posted in the top level of this forum with no indication of which app.  i would suggest you check to see if the app/data field has a "contact the developer" link, a specific sub forum thread for support or, as a minimum, include the app/data field in the subject.  Hope this helps you get a response. 

On the device itself, under settings>system> units, set distance units.