Branch change from EE to CSE is easiest at IIT Jodhpur. Here, students who have scored a 9+ CGPA can change their branch as there are no additional criteria. If you are talking about an easier branch change from EE to CSE, it would definitely be IIT Jodhpur, as here there is a rule that if you score a CGPA of 9+ then you can change your branch to any branch of your choice.
When my friend was a student at IIT Mandi a few years ago, she told me that 10 students from the EE branch changed their branch to CSE and a total of about 18 students from other branches changed their branch to CSE, and about 10 students from different branches to EE. Surprisingly enough, the last student to change his branch to CSE had a CGPA of 8.67.
Thus, branch upgradation is easier at IIT Jodhpur than at IIT Mandi.