I amended '19 taxes. IRS found cpl other chgs. My ? is do I chg my '19 rtn & make chgs to 1040-x as IRS did? Do I redo '20 assuming '19 chgs affect '20?

[cr81dr00]

IRS made changes to "Other Income" and "Schedule A". Do I make those changes to 2019 return and then see how it affects 2020 return? Do I then amend 2020 return?

[Critter-3]

Do I make those changes to 2019 return and then see how it affects 2020 return?  CORRECT

Do I then amend 2020 return?  YES