Trace a copy of basic block. Draw the hem at mid calf, keeping the same width as hip line, then reduce 2-3cm from the sides.
Mark the waistline and discard back dart: take half of it from center back and half from side seam. On front, discard only the skirt dart from side seam (keep the underbust dart for manipulating it afterwards).
On both back and front draw the new neckline. On front only, draw the slanted underbust line, the straight piece in center front.