Hello Aspirant,

Hope you are doing well!

If you failed once that means you appeared for the compartment exam to qualify it,and now you are unsatisfied with your scores, you think of reappearing.

Then,yes dear you can give the exams again,in the form of Improvement Exam

you don't need to give the complete board exams again,if you are unhappy with a particular subject you may apply for those particulars subjects only or even others if you are interested in.

Hope this was helpful !
All the best!

Keep Smiling :)