After the TurboTax online tax return has been completed and filed you can amend the return.
Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.
See this TurboTax support FAQ for amending a tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...
