Adjustment of Status - I-485

Hi, I received USCIS denial letter of my employment based 485, very shocked and sad! The letter said I am inadmissible to the Untied States Under INA212(a)(6)(c)(i) for fraud or willful misrepresentation of a material fact. I am not qualified to adjust status. I was arrested in 2003 for petit larceny, the case was dismissed and sealed in the end. In 2009 when I applied H1B visa, I did not mark Yes to the question of arrest. I thought my incident in 2003 is not a crime or larceny, and it has been dismissed. I have never thought this is a big problem. My attorney told me the USCIS officer misunderstood the
Law, I can file a motion to reconsider and my case probably be reconsidered and finally take my 485 back to pending or approved. I am not sure about this. Do you think I still have chance to challenge the denial decision? If I file Motion to reconsider, what is the key view point can I persuade the office to reconsider and approve my form? Please help!!!