Hi Aspirant,

According to most of the boards in India.you cannot repeat 12th boards with different choices of subject.However in case you want to repeat you have to take admission in science(biology) according to your class 10th marks and then you need to reappear and study class 11 from first and then sit for board examination.I would suggest you not to waste the time like that and decide the career you can pursue with your already given 12 exams and then proceed further.

Hope it helps!!