Can I change from an L to S1 visa in Beijing with out leaving the mainland

Hi, My kids and I are accompanying my husband who is a student in Beijing , we have the L (tourist), once we get there he gets his residence permit for the year, is it possible for us to change L to S1 during our stay there or do we have to apply in our own country for it? Do they change visa types at the security Beaureu in the mainland?