This neck is going to make a syrup tin uke, so will not be replaced.
Assuming you have no plans for the body, I'd cut it away (body that is, not neck). Saw along the side of the neck towards the bridge, on each side. Join the cuts about 2 inches past the neck body join.
You now have a neck with some scraps of body attached. Remove them with chisel, plane, knife - whatever. You will be left with neck + neck block, and can decide how best to fit it to your syrup tin.
If I guess right from the other thread, the syrup tin will be the body and the stainless steel thingy the resonator cone. If so, your neck is probably too short - you'll need to extend it to meet the body (and I'd take it right through the tin, to save the string tension buckling the tin). The magic distance is your current nut -> bridge measurement - the saddle on your build needs to be the same distance from the nut.