date modified

hopefully this hasn’t been answered before..I’ve tried searching around in here and on google and didnt’ get what I was looking for.

Anyway, I was trying to add a “date modified” that woulds show up under a post if that date was different than the date posted. which I think I figured out how to do, but now I’m wondering if there is a way I can change the date modified field? similar to the method the advanced editing allows you to modify the date posted field.
I’m not sure if I can copy-paste to that bit of code and the touch_time function and modify them to add a new date modified field?=.