I have been crocheting panels that are to be made into a play mat for our great grandson. I finished all the panels, edged around them, and just laid them out on the table so I can match them up and begin sewing them together. I discovered that one panel is too long. (Guess I got carried away.) Is there a trick to undoing the edging around the extra rows and deleting the rows or do I have to start all over and do another panel?