If it's the style I am thinking of, you can fully depress the pedal (tell it sad stories) then clamp the cable with vise grips, release the pedal and it will move back free of the cable. This will allow enough slack to work it out of the hook, then release the vise grips and slide the cable out the back. The challenge is putting it back in, I have been successful with sliding it in the back of the pedal assembly, take one pair of vise grips and clamp it at the end of the cable pull it as far as you can and then use another pair of vise grips to clamp it at the base to keep it from moving back, remove the first pair of vise grips and return it to the hook in the pedal.
If it is a different style, I just wasted your time.
Post a picture if you can.