Place the bird in a large bowl, make the breast face you, pull back the skin to expose the wishbone, and trace along the bone with a boning or paring knife, cutting just deep enough to loosen it. At each end of the wishbone, there is a joint connecting it to the rest of the skeleton, cutting which will enable you to bend the wishbone upward and slide your knife underneath the pointy bit where the two ends meet. Then, pull the wishbone out with a twisting motion.