If you used TT to file the original return then amending has always been an option however you will need to use the downloaded version and efiling is no longer available.
See this TurboTax support FAQ for amending a 2019 tax return - https://ttlc.intuit.com/community/tax-topics/help/how-do-i-amend-a-2019-return-in-turbotax/01/123845...
