Two questions: (1)If a student travels to China on a student/business F visa for a summer cultural/study exchange, can the student change that F visa to an X visa while in China if the hosting organization makes all the arangements? Is this possible?

(2) If the F Visa cannot be changed to an X student visa, but is valid for one year of multiple 30 day entries, can the student simply walk into Hong Kong once a month and then re-enter China on his F Visa throughout the year until his F visa expires? Or, does he have to stay in Hong Kong for a few days before he re-enters China?

Thanks for the help.