Hello Kunal,

In Engineering, you can change the branch once you ave completed your first year.

After the results of the first year are declared, there will be a notification regarding the branch change by the University in which you are studying or by the college itself if it is autonomous.

Then you need to fill the form and wait for the merit list to be declared. 

But the thing is that only a couple of person gets the chance to change the branch based on the merit list.

It also depends on if there are any vacant seats in the branch which you are willing to join.

So one thing you should worry about now is maintaining good academic scores so that if there's any chance, you might get through it.

All the Best!!

Dear Kunal, Yes you can change the subject beginning of the First-year because of most of B. tech 1st year of all branch are same the core starting in 2nd year. So you also change in starting of the 2nd year but it is best if you change in 1st year. You need to talk your Instituted counselling they help you.

All the best.

In most engineering colleges, there's an option to change branch after 1st year for that you need to have fairly good CGPA in first year.
It is possible to change your branch after completing the1st year of the engineering course within the same University.