Dear AK.
To make a cowl neck from a jewel neck. Fold a large piece of paper down about three inches. This will become the facing for the cowl. Measure from your center front neck base down to where you want the drape to go. Move the pattern piece that measurement over from the center front, and trace the pattern. Leaving the facing folded down, cut out the pattern. Change the grainline by drawing a square with one side parallel to the center front. Then draw a grainline from the top right hand corner of the square through the bottom left hand corner.
You can have a cowl in front or in back, but not both, unless you have some way to control the drape. Essentially what you're doing is widening the body, so it would fall off in not controlled front or back.
Teri