could I go in one way ticket and what about if need to change visa status?

Hi Aditi, since you have already got the family type, I think it does not matter if you go in wth one-way ticket. After being admitted by a school in China, you can get the admission letter JW201 or 202 form first through your school and then go to the local Exit & Entry Administration Department to change the S type into X type. If the officer says it's not permitted to do so, you have to go back to your country and apply for the X type. Your S type will authomatically expire after you get the X type.