With your index finger, gently wiggle the bill to help loosen it up from the fetal position. As Rose Quartz said, if it bleeds, you can put a bit of toilet tissue on the bleeding spot and put it back into the incubator for an hour before trying again. Each attempt you make towards freeing it from the shell, work the bill loose from that fetal position, once freed without tugging you can turn the egg upside down over your other hand and without yanking (the chick is still attached to the shell by its umbilical cord, and you DON'T want to yank on that!), allow gravity to encourage the duckling to fall into your hand... Once this is successfully completed (could take a few rounds of incubator time in between), place the chick, still attached to its shell back into the incubator for an hour; you're hoping that the duckling will kick the shell off, or at the least, that the veins dry up sufficiently that you can sever the umbilical cord at the narrowest point midway between shell and duckling. Again, if it doesn't look like the veins dried enough to safely sever the connection, then place the duckling back in the incubator and wait another hour before trying again. You don't want to cut too close to your duckling, preferring instead to cut closer to the shell. You'll have to use your good judgement on when to let the duckling rest in the incubator between these stages of assisted hatching. You and your feathered family are in my prayers.