My son was getting SSI and then when his father retired he was switched from SSI to Social Security with Disability. I am confused, because I need to know does this mean that he is getting Social Security now or is it still SSI? Can he work while getting Social Security or getting SSI. One of them has a formula to use and I am not sure which one. Maybe if someone can help me. I need an answer by Monday, March 10, 2008.