At my job....we wear safety vests. Love it. It reduces risk of injury by insuring you are seen. The problem with my safety vest was the pastic window pocket. When its hot outside.... heat from the sun would feel as if it concentrated there. Then to make matters worse...things would fall out of it as the plastic window was rigid.
The solution....soft, organdy fabric....used the trim that came from the window pocket like bias tape and bordered some organdy prepped like a drawstring bag. Then I stitched it down where the original pocket was and this is the result.
Now the pocket moves with me, is still see-thru as required and when carrying something important in it...like my id badge...I can pull the drawstring to prevent it from falling out.
Should you attempt this...turn item over and trace the stitch line from the original pocket with a pencil or washable felt marke...this way there's no guess on where to apply the replacement pocket. The rest is just basic....so basic in fact...it only took me 15 to 20 mins to sew it by hand. Try it.