If you need to make changes to a tax return that has already been filed and accepted by the IRS or a state, then you would have to amend the tax return that was filed.
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-a...
Amending a tax return with a tax refund. more than three years after the original due date, the refund will not be paid.
