Is the yolk fully absorbed? If the chick is good just stuck to the membrane of the egg, first be sure there are no veins out into that part of the membrane, then carefully tear away the part of the membrane that is stuck to the chick from the rest of the egg. This will leave a little piece stuck to the chick. When the chick starts to dry you can wet a cloth and apply moisture to the piece of membrane. Then just gently work your finger under it going with the grain of the feathers/fluff. If it's shell that is stuck I'm not really sure how getting that off works, maybe someone else could help with that.
Two more things, first, if you have other chicks set to hatch you shouldn't open the bator to help this one chick or you could compromise the whole hatch. The humidity has to stay fairly high so that all the chicks can hatch out OK.
Second, you should change the title of your post to be more specific, I suggest "HELP, chick stuck to egg" You will get more responses faster that way.