Amend for a decrease in NOL from an amended passthrough?

Client elected to carry-forward-only a one million dollar loss from his s corporation in 2019.

Or so we thought.

Turns out, after working on the 2020 tax return, he discovered that there was a mistake on the books and he only lost $700,000 in 2019. We amended the 1120s.

His 2019 individual return had very little activity other than the loss coming through with the K1.

Do we amend the 2019 individual tax return?

Or do we just "correct" it on the 2020 personal return instead?

Or do we just "correct" it on the 2020 personal return instead?

You use the proper carryover amount adjusted for the proper income that should have been reported in 2019. I usually draft a return and keep that in the file as support for my NOL to 2020.