The lawyer replied as following:
The filing of I-485 does not automatically terminate F-1 status. The decision that an alien student loses his/her F-1 status can only be determined by U.S. citizenship and immigration service only. Employer or school is not in the position to make such a determination. Your OPT is also valid unless the USCIS states otherwise. Moreover, you are eligible to change from F-1 to H-1B.