Give it a good while to either have a go or to absorb all the blood from the vessels inside the egg and to get in the last of the yolk sac. Leave it as long as you dare before helping, and if you feel you have to, just carefully pick away a small bit of shell eiter side of the pip and carefully see if you can peel back the membrane. This should give the chick enough room to turn and zip. If not, try a bit more, but just be careful not to rip any membrane as it can then bleed to death. I find using a small sarp knife and kitchen paper soaked in warm water wrapped around the egg helps to keep it moist when out of the incubator, and keep a heater nearby if the room is cold. Put it straight back in when you have done what you need to. If you have to help it take off the end of the shell, at least let it kick out on it's own. I thought I had one do that last year but it just pipped very low on the egg and was still the right way up, so be careful. You could just pop a hole in the fat end of the egg where the air cell is and this will soon tell you which way the chick is, if there's a hhole in the membrane there it's the right way up: leave well alone!