To know about the procedure or hardness to change/upgrade your branch, you must first know the prerequisites for the same. There are two factors based on which branch up-gradation depends and these are-
Now, seat availability is a crucial factor because, the more the number of seats, the more will be the chances of branch up-gradation.
Since IIIT Allahabad is shutting down its dual degree programs, the number is supposed to reduce as the branch up-gradation will be restricted to ECE-IT conversions only.
Now the other factor i.e. SGPI, 9+ can be considered safe for branch up-gradation from ECE to IT. It might go as low as 8.7 but to be safe try to score 9 SGPI.