See as permanent address don't change so NTA have assumed that the student won't mistake there as a result they don't provided the option to change. Now you can do a thing that you left your present address as it is i.e., your permanent address. There won't be very much problems about it in future. If you have filled the city preferences correctly then you will not face any problems ahead.

For the NEET 2021 revision tips visit the link below:

https://medicine.careers360.com/articles/revision-strategy-for-neet

I hope this answer helps. All the very best for your future endeavors!