Dear student,

No you can change your iit, even if you score good cgpa in your first year, might be you can change yiur branch if you are not happy with you initially allotted branch (it doesn't happen in all iit's). Admission in all the iit's are carried out by there own procedures, however you get admission in an iit through a common counselling- josaa, but that does not mean that you can change the iit you got admission in after a year. There is nothing like upgradation of iit's but you can upgrade your branch if you want to.