Modify 2021 return in 2022

[suvigb]

Hello,

I realized that in 2021, I could have claimed a Ontario Staycation credit using form ON479. I want to amend by 2021 return for this claim.

When I open the older year's return, it just asks me to copy the data into the new return. Can I modify the 2021 return and add this 1 tax credit.

thx
Suvig