To seal the shoulders, measure and extend at least 2 inches from the pivoted notch and pin it, leaving an opening for the sleeve. Repeat this to the other shoulder.
Using the sewing needle and thread (doubled for durability), back-stitch along the edge’s original stitching line to camouflage your handiwork.
Ta-da! You’ve now created a bateau neckline and open sleeves.
To close the side seam from the waist, start with the wrong sides together, measure 22 inches from the hem, and pin both scarves together.
Using your needle and thread, stitch from the hem up under the rolled edgings.
We left a large gap between the shoulder and waist on purpose. Why? Just thread your best belt through the gap to let the back flutter like a boxy cape. Clever, huh?