You can file the Form 8606 on its own. There may be a penalty associated with it, but not if you can show just cause for not filing it with your returns.
Take a look at the following TurboTax help article for more details about how to file the Form 8606. The information is in the link for If your conversion contains contributions made for 2023 in 2022 toward the bottom of the article. The possible penalty for filing Form 8606 is also discussed there.
How do I enter a backdoor Roth IRA conversion?
As for recharacterizing the Roth IRA conversion back to Traditional IRA, as of 2018 due to the Tax Cuts and Jobs Act, that is no longer allowed. You may recharacterize a Roth IRA contribution, but not a conversion.
See the following IRS FAQ for more information:
IRA FAQs
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