I need to roll back a reconciled bank account because the starting balance is off.

It's great having you here in the QuickBooks Community, @menro.

You can consider using the Audit log to recreate the deleted reconciled transactions, and manually mark them as reconciled. This will correct your beginning balance for the current month without having to undo the entire previous reconciliation of your bank account. I can guide you through the process.

Here's how you can view the deleted transactions from the Audit log:

1. In your QuickBooks Online (QBO) account, go to the Gear icon.
2. Select the Audit log.
3. Choose the appropriate option from the User and Date Changed drop-down lists.
4. From the Events drop-down menu, select Deleted/Voided transactions.
5. Click on View to see the details of every transaction.
6. To help in the task of recreating transactions, use the audit log on another browser tab.

Just a heads up, kindly ensure to enter the recreated transactions into the original bank account.

Once done with recreating the transactions, here's how to manually mark them as reconciled:

1. Go to the Gear icon.
2. Select Chart of accounts.
3. Find the account where the recreated transactions are, and click on View register.
4. Select the transaction and click on the box from the checkmark column until you see an R. This marks it as reconciled.
   

As further help in correcting your beginning balance for the current month, let me add this article: Fix issues for accounts you've reconciled in the past in QuickBooks Online.

Let me add this article as a guide in printing and viewing your reconciliation report: How do I view, print, or export a reconciliation report?

Keep us posted if you have any updates recreating the transactions or reconciling accounts in QBO. We're committed to offering ongoing support. Take care.

Thank you for getting back to us, menro. Let me chime in and help you fix your starting balance issues so you can begin reconciliation. 

Recreating the previously deleted entries from a past reconciliation will not cause duplicates. Instead, it's the direct way of bringing back the deleted data. If you imported the entries in the Banking page, it will not cause duplicates yet. You still have to categorize them. 

Since you have already recreated the transaction, we can manually Find match or match it to the imported data. This way, we can ensure they aren't added to your register as separate transactions.

Afterward, we can exclude the unneeded transactions to prevent duplicates on your account register. Now, we are ready to reconcile the account. However, if you still encounter discrepancies, you may run discrepancy reports to ensure the difference between the ending balance in QuickBooks and your bank statements is $0.00.

Also, you can check out this article for more info: Fix issues for accounts you've reconciled in the past in QuickBooks Online. 

Lastly, since you mentioned you have an accountant, I recommend inviting them as an accountant user and letting them undo the entire reconciliation period. 

Don't hesitate to leave a comment if you have additional concerns about correcting your reconciliation in QBO. The Community space is available anytime to offer assistance. Keep safe always!