I have 2009 Ford Escape and just go oil change. However it says "change oil". I understand you can get rid of this message by resetting. Where is the "reset" button?

This is how it works on my 2010 Escape. There are 3 buttons to the lower left of your steering column (Info, Setup, and Reset):
1) when it's displaying the "oil change required" message, hit the "reset" button to get rid of the message2) then hit the "Setup" button twice and you'll see the "oil life" screen, which is now at "0%". It tells you what to do next (i.e. "hold reset" until it says 100%).

You need to take it to your dealer shop cos resetting is done through the computer