Dear Karthik, for rejoining in First year in another University, you mught have to qualify for their Entrance Examination. Lateral entry will be not an option because you are not opting for 2nd year but want to rejoin 1st year. And then, you might have to pay the full course fees to your current college as they are foregoing a potential candidate for that entire duration of the course. For that you need to speak to your Administrative authorities.