Hello @megcusimano,
You can manually undo your reconciled transactions since the option to delete a reconciliation is unavailable. You can do so by removing the R (Reconciled) status of all your transactions in your bank account register.
In addition, here's an article you can read to learn more about how you can manually undo your reconciled transaction: Undo and remove transactions from reconciliations in QuickBooks Online.
But you can also consider contacting your accountant. He/she has the option to undo your entire bank account reconciliation with his/her QuickBooks Online Accountant account. Thus said, here's how you can contact and invite your accountant:
- Go to the Gear icon.
- Under Your Company, select Manage Users.
- Select Accounting firms.
- Click Invite.
- Enter the name and email address of your accountant.
- Click Save.
To add, here's an article you can read to learn more about how you can invite your accountant: Invite or Remove an Accountant.
Lastly, I've also included this helpful article in case you need some ideas about your reconciliation report: How do I view, print, or export a reconciliation report?
If there's anything else that I can help you with, please let me know in the comment section down below. I'll be always around ready to help.