Trace front and back separate, then:

• on both pieces lengthen shoulder line outwards by 4 to 6cm, then drop the new shoulder point by 2cm
• on both pieces drop armhole by 2 to 4cm and redraw it
• on both pieces, adjust length first, then flare 4 to 8cm from sides and blend to zero at waist
• on center back, add 4cm outwards (15cm high) for the slit
• on front, measure down 6cm from new armpit point and connect to bust point. This is the line for french dart, cut through it and close previous shoulder dart.

See how shoulder dart is manipulated? Redraw its apex 2 to 3cm inwards so that dart is shorter and does not give the effect of pointy breasts.

Make sure shoulder line has a smooth curve in the transition between actual shoulder area and cap sleeve.

Then widen neckline:

• drop 1 to 2cm in center back
• widen by 2 to 4cm on shoulder line of back and front
• redraw back neckline with the two new points
• redraw front neckline to original center front.

Now get front only. Here you see the new apex of french dart, made a bit shorter.

Redraw waist dart moved to the side, 8 to 10cm from side seam at waist, then quare up and down. Dart width remain consistent, dart bottom length is consistent while dart upper apex reaches bottom line of french dart.

Draw the flap 13 to 16cm long and 4 to 5cm wide, with rounded bottom edges.