Use a Seam Ripper
Here’s a fact: If you sew, you will “unsew.” Simply put, sometimes it is necessary to remove a line of stitching. What you need to unsew is a sharp, good quality seam ripper. It is a must-have tool in your sewing kit; make friends with it.
All seam rippers look pretty much alike. Some have some extra bells and whistles, such as a built-in light, or an ergonomic handle. Choose one that is sharp and fits well in your hand.
The working end of all rippers have the same components: a pointed end, a curve that holds the sharp “blade,” and a shorter end that’s topped with a ball.
To use it, slip the pointed end under the center of a stitch, keeping the pointed end parallel to the fabric. (If it’s pointed toward fabric, you’ll probably cut through the fabric.)
Push forward on the ripper to make the “blade” in the curve cut through stitch.
At the beginning and ending of a seam it’s likely that several stitches are stacked atop one another to prevent stitches from releasing. Cut through each stitch.
Working on the same side of the fabric, cut through every fourth to sixth stitch.
Turn the fabric over. Slip pointed end of seam ripper under a single stitch but do not move stitch to curve of ripper.
Lift up on ripper while holding thread in place. With the pull exerted on the thread, the stitch will release.
Pull on the thread with your fingers to release the entire line of stitching. The fabric pieces should separate.
Remove any remaining stitches by picking at them with pointed end of ripper.
Press a piece of cellophane tape atop fabric where stitches were located, then peel the tape away to remove loose thread ends.
Press each fabric piece and it will be good as new.
CAUTION: Don’t use a seam ripper between layers of fabric. You’ll run the risk of cutting through fabric and stretching the fabric out of shape.