Why are you asking? Why do you think you need to clear your return? Do you want to log into your previous account to do your return? If you want to use your old account you can just leave and abandon the new account. Then you would have to start over in the old account.
Do you need to find your old account? How to view all your accounts
https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/many-intuit-accounts-turbotax/L9aVfKS1Z_US_en_US?uid=ll5g6zcx
It's common to end up with multiple accounts. First LOG OUT of whatever TurboTax account you're logged into right now. Then use this TurboTax account recovery website to get a list of user ID's for an email address. Run the tool against any email addresses you may have used
https://myturbotax.intuit.com/account-recovery/