Yes Student  you can change your Subject after class 11. I know in my school many friends have changed their Subject but the only condition is that you have to pay extra money/fees to school. In many CBSE Board Schools it is between 1500-2000 . But you should confirm This in your school. But in my opinion changing from Commerce Stream To Science Stream in Class 12 can affect your results. Rest is your choice . Whatever you like you can do it.

Hope you understand this very Well and All the Best!

Thanks for Support and Have a nice day!!!

Hello student ,

Yes , you can your stream from commerce to science after 11th standard if your school cooperates but it also depends from which board you were studying . So please mention your board also so that I can guide you else you have only one way left with you and that is repeat you class 11th . See some schools used to do registration two times and if they are asking from you in 12th also to do registration to confirm your subjects then you may ask them to change your subject or else you will have to read class 11th once more .

Hope it helps !