Change aspect ratio on MKV movie file

Hi, need some guidance ,

I have a moviefile in MKV format and it`s in 4:3 aspect ratio (720 x 480). I would like to recode this file into a 16:9 aspect ratio instead by cropping out some of the information at top/bottom.
I have XMedia Recode on my PC but i`m not sure how set the software for this task.

Any help is appreciated :)