Hi there,

Freezing a choice means that you have accepted that seat allocated to you and you must pay the fees to report to the concerned institute.

You can visit the official website of the ap eamcet counselling authority and then can check about the rules and procedures related to the counselling in  the given exam. Generally after freezing an option you cannot change the seat until some of your seats are not left or due to some any other issues.

Thus, to get  a more detailed idea that whether you can change the options in the 2nd round of the counselling after freezing a seat in the 1st round depend on the counselling criteria set up by the authorities which you can know by visiting the website.

Hope this resolves your query.