B2 to M1 to HB1 /B2

[nsk]

Hi,
I came on USA on B2 visa ,then here I got my Status change as M1.
I would like to ask you ,that can i change my M1 status to HB1 or B2 again at the end of my course here in USA,or i have to go back home.
In case i get to go back home than what will be my status B2 or M1 as i got multiple B2 visa stamp on my passort .
Can i apply for HB1 while staying in usa after completation of my course or has to come back home and apply for HB1 through usa ambassy .

Need your help!

waiting for your reply.

thanks