No .

once you have alloted a College then you became in safe zone. You never go down in the choice filled list , even your college is not upgraded . If no any upgradation happen then you will alloted the same coleege and branch which was alloted earlier .

Best of Luck .

Hello Nishu. 

No, your alloted college will not get cancelled if you do not get a college in upgradation so you can apply for upgradation. You get a college according to the list you have applied in sequence. Because it is an automatic auto upgradation system. It only gets upgraded if you get a college of your higher preference. So don't worry.  Your alloted college will not be cancelled.

Hope it helps.