2023 amendment

See this TurboTax support FAQ for amending a prior year tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-already-filed/L4VjJ9BA2_US_en_US?uid=ld1n99kr

To access your prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/

Start the 2024 online tax return by entering some personal information then click on Tax Home on the left side of the screen.

On the Tax Home webpage -

Scroll down to the section Your tax returns & documents.  Click on the Year 2023 and Click on Amend (change) 2023 return

If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created.  TurboTax does not store online any returns completed using the desktop editions.