Hi Bharath,
Yes, in case of 2nd or any other round of medical counsellings you again get a chance to fill up your choices with a new prefrences all over again at the time of choice filling and locking for 2nd round of counselling , similarly as you had done in your 1st round of counselling.
Also, it doesn't matter what you had chosen in your 1st round of counselling. You get a fresh and new chance to change your choices in 2nd round of counselling though.
Good luck.
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