Amending tax refund

Hello,

 

I saw the news saying " $10,200 of unemployment payments are now tax-free for households with an annual income under $150,000." that you could get the tax refund for on 2020 tax report that's already been calculated.

 

If order for me to get this benefit, should I amend the tax return?

 

I also didn't get the second stimulus for dependant.

 

I filed the 2020 tax report and already got tax refund.

 

What should I do to get all corrected?

 

Please advise.

 

Thank you!