Hello student

Yes you can do your internship in any of the colleges of your choice.

But there should be a review for whether the college / university you are willing to change for internship BMS is registered and approved by MCI Medical Council of India and authorised to enroll for  to get permission of  internship programme.

As you have mentioned that you want to change your internship from TN MGRMU to Kerala University for rotatory internship program so it can be said that most of the medical colleges in Kerala is approved by MCI as well as the Kerala Health Science University also.