A friend of mine who works for a major corporation was just told by the company that they had a labor certification approved for another person with extremely similar position and background. However, the person had already married an American and got the Green Card through marriage and does no longer need the approved labor. Instead, the company and their lawyers extended this approved labor to my friend, but did not tell any details how it works. All he was told was that they can do a "labor swap." Does anyone here know what a labor swap means and how it works?