Sure. Lower the third 1/2 step. For the G chop it's 7-5-2-3, where your index finger is fretting a B note which is the third in a G major chord. Drop it to the first fret and play 7-5-1-3 and you have a G minor. Determine which note is the 3rd for any other chop chord and lower it one fret (1/2 step) to make it minor. This is where a basic knowledge of theory can help you.
"I thought I knew a lot about music. Then you start digging and the deeper you go, the more there is."~John Mellencamp
"Theory only seems like rocket science when you don't know it. Once you understand it, it's more like plumbing!"~John McGann
"IT'S T-R-E-M-O-L-O, dangit!!"~Me