[SOLVED] Offset travel along a path?

I have a rig parented to a path so it will follow as a function of time. Is it possible to start the motion at an offset time? ie start the motion at frame 120 and end at frame 600?

Figured it out. You need to modify the F-curve (evaluation time) first you have to remove the modifier that is on it, then you can insert keyframes ad-hoc.