Visa Extension and re-entry to China

Hello,
I have a business visa for 90 days which expires on 30th June. Can I change my visa to tourist visa in China? Furthermore, I have a special passport that allows me to enter China for 1 month without any visa. If I exit from China on 30th June and reenter after 5 days with my special passport, do you think will it be a problem? Thank you for your help,