You need to go back into the state return to change that answer. Each state is set up differently, but the question should be after the deductions section. It will ask if you want to apply your refund to your 2020 tax. That is where you change your answer.
If you want to reply with which state, I can give a better answer. Another option is to delete the state as that will reset all the questions. Then you can enter the state information again and skip applying your refund.