For example I am selling a Tank top on our website. I have a child small in the blue color available and a child medium in the purple color. They are being sold under the same item and I gave options of Size (Child Small annd Child Medium) and Color (Blue and Purple). If they select the option on a child small and click the blue it selects them, but then they decide they want the purple in the child medium they can not go back on the website and deselect the option. Since I do not have a Child medium in the blue they can not select  CM, and since I do not have a purple available in the CS they can not switch their color. Is there a way to put a NONE button as on option so they can change their selections, or is there a setting where they are allow to deselect an item once selected? I have now added my own option of none but it puts items into my inventory in order for me to have that option for them to deselect.