I got admission in IT at VIT Vellore in category 1. Can I change it to CSE in category 2?

First of all I don’t think its possible to change now (but rules keep on changing so better you check with admission officer )and secondaly it doesn’t matter whether your branch is CSE or IT because at the time of placement you will be eligible for all the companies which comes for cse students provided you met the cgpa cutoff companies.