Hey,

As far as your question is concerned I don't think so it is possible and in fact acceptable. You are already doing your graduation. So how can you just do your 12th studies again.

Students in CBSE board are allowed to appear for their improvement exam only in the consecutive year of their passing of 12 th exam. Think yourself how will you be able to go in decreasing order of your studies. Doesn't sound right.

Hope that solves your concern.

Thank you.