First, draw the new neckline widening neckline 4 to 6cm from high shoulder point. Widen shoulder dart by 1,5cm at front neckline.
From center front add 6 to 8cm outwards for double breatsed buttoning.
Then redraw armhole inwards by reducing shoulder top by 1 to 2cm.
Redraw the hemline shaping it slightly shorter at sides.