my niece came to the united states on a B-1 visa she was given 3 month at the port of entrywhich expires on 07/20 . she applied for school and she got accepted for the fall semester. she need to to be in status in order to changer her status in October. can she apply for an extend of stay based on this reason so she can be on status when she apply for the change of status. she also have an invitation to a conference in October which she loves to attend.