Yeah, it's very simple. You right handed? Take your left hand and squeeze the cable and riser together somewhere below the grip. This will rotate the cam, usually enough to get the screw loose. Take the screw out, replace the mod and do it again to put the screw back in.
If by chance the limbs are bottomed and you can handle the weight then either back the limbs off about 3 turns or squeeze the cable as I instructed and use a zip-tie to hold it while you do the work. When you get done just hold the cable while you cut the zip-tie with a pair of scissors.
After you're all done with this then go get you a Bowmaster portable press. It works wonders for little jobs like this or replacing strings and cables. It'll last for years and can even fit in your hip pocket if you're a traveling hunter.
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin/Rytera Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver