Ritesh,

There are two types of branch sliding in BIT MESRA. 

1. At the time of admission

Apart from all the rounds of counselling, there is an internal sliding at college level only. You have to opt for it by filling the branch change form. If you rank and available vacant seats resonate positively you may get upgraded to any of the branches mentioned in your choice list of the internal sliding form.

2. At the beginning of second year

To get your branch changed after first year you need to score heavily in first two semesters. Simply put, you must be amongst the toppers ( considering you belong to general category ). But this doesn't guarantee a seat in branch of your choice.

What also matters is the availability of seats. Like for example, last year none of the students who applied for a change in branch could get a seat in CSE branch due to same reason.

HOPE IT HELPS