How to migrate from Amity Unversity Noida to another institute?

At this matter you have to ask to concern department you university because they have option to transfer your enrollment number to other institute

Which colleges require they own form to be filled up if i want to apply with cat score?

He Amity Group had 50,000 students enrolled at its various campuses across the country, paying tuition fees from Rs28,000 per annum for Amity International School to Rs5 lakh for a two-year postgraduation course in business administration at Amity University.