Are you able to delete a month of reconciliations in Quickbooks Online?

I appreciate you posting your concern here in the Community.

Let me share information about deleting a month of reconciliation in QuickBooks Online (QBO). 

You can only unreconciled one transaction at a time in QBO. In this case, I suggest reaching out to your accountant, where they can undo an entire period at once using QuickBooks Online Accountant. 

I can help you look for one if you don't have an accountant. Feel free to visit this page to find an accountant for your business: Find a QuickBooks ProAdvisor.

Furthermore, if you want to manually unreconcil each transaction to undo the reconciliation. You can follow the steps I’ll provide below:

1. Go to Gear Icon ⚙, then Chart of Accounts. 
2. Look for the reconciled account, then select View Register.
3. Review the check column. If the transaction has been reconciled, you’ll see an “R”.
4. To expand the view, click on the transaction.
5. In the checkmark column, tap the box with the “R” until the box is blank. This removes the transaction from the reconciliation.
6. Select Save, then close the account register.

Kindly refer to this article for more information on the undoing of a single transaction from completed reconciliations in QBO: Undo or remove transactions from reconciliations in QuickBooks Online.

Additionally, I have included an article to help you if you come across reconciliation issues: Fix issues at the end of reconciliation in QuickBooks Online.

Feel free to drop a comment below for further inquiries with reconciliation in your QBO, I’ll be here to answer your questions at any time. Have a great day ahead!