Hello Manasi, 

In the notificcation itself Symbiosis Law School has made it clear that the category which you have opted for while filling the application form cannot be changed under any circumstances later on. Also, they have mentioned that there will be seperate merit lists for BBA LLB and BA LLB in the notification.

If you have selected BBA LLB I recommend you to not flicker away from it as SLS is an elite instituiton in the field of Law and any opportunity to be a part of it should not be vandalised.

All the best!