I think with the blood veins showing, you should leave it be. I'm not a hatcher, but from what I read, they can bleed to death if the veins still have a lot of blood in them.
Wait to see what others say before you try anything.
I let my chicks go until it falls off. I've heard of people cutting it, but I didn't except for 1, it dried and didn't come off. I cut it closer to the egg before I put him in the brooder.
Finally the little guy is detached from his egg and now can move freely ! Thanks to all that gave me some really good advise first time hatching ducks so glad I now know for next time .