NIT Calicut provides an option for internal sliding. If you are among the top two students from your branch, you can change your branch after the first year. Apart from these, many other factors are taken into consideration.
Many of my friends are studying at NIT Calicut and therefore, I would suggest you not opt for NIT Calicut if you do not get CSE or ECE. The institution gives the least importance to its students. Other than departments of CSE and ECE, the placements are pitiful.
You can check their website and find out the department-wise ratio of faculty members to student ratio if you do not have trust in what I am saying. Check their placement statistics and you will be surprised by seeing the number of core companies visiting the campus during the placement drive. There are numerous other problems as such.
To be precise, the institution's rank has drastically fallen from 9 to 45. I would be of no surprise if it goes down more.