How difficult is it to change branch from ECE to IT in IIIT-Allahabad?

Well that is neither difficult nor simple. It actually primarily depends on how many students are opting for IT in IIIT Allahabad. It is almost impossible to guess what the cut-offs are going to be. Although there is a tough competition among students who wish to go for IT from ECE and you will have to clear that successfully.

How many students in your year are wishing to transfer from IT to EC will also matter in this aspect. Hence, rather than planning and thinking about what the cut off will be, the only thing that you should be doing is working very hard to score the best CGPA in your batch because only that is in your hands. Scoring CGPA above 9 makes it very easy for you to transfer from ECE to IT in IIIT Allahabad.

Obviously you should have all the basic knowledge and understanding such as C, C++, Java etc. before you think of switching your branch.