If class has already commenced, you will have a very difficult time making any switch. The best time to select a college of one's choice is when admission process is ongoing. Post admission, seats get filled; also most colleges don't have the resources to conduct mid-term counselling and interview which is why changing a college is very rare.
Anyways, I would suggest you get in touch with college authorities to find out whether there is a process for making switches and the eligibiity criteria.
Please specify the name of the admission or exam name to get a better answer.