AOS status can be change to H-1, but most likely need to go outside U.S. to get a H-1 visa to activate it. Some people intend to use EDA to save H-1 time. So, if soemthing happen with their current employer or their I-485, they can pick up the remaining period of the 6-year H-1 limit. See the website for more information: http://www.immihelp.com/greencard/adjustmentofstatus/eadap-hl.html