Start from a basic block with darts and zero ease.

On the back, draw the straight neckline and draw 3 panels discarding the dart volume in between them and from center back.

On the front, draw the neckline and widen the shoulder dart at it by 1cm.

Extend the neckline and draw the band forming the sleeve.

Draw the slanted line for the panel cut and draw two slash lines at bust height for the dart manipulation.

Draw the new waist shape.

Trace the two separate pieces of the front.

On the center, close both dart opening them in the new slash lines.

Close the dart also in the side panel.

Cut the center front from the darts all the way to the center, then straighten this part.