How do I undo a reconciled month in order to make corrections?

Reconcile undo is under the accountant tools, so either have an accountant log in and use it, or invite yourself as the accountant and log in

Hello there, @leanna100.

In QuickBooks Online, you can manually unreconcile each transaction. You'll want to follow these steps:

1. Go to the Accounting menu.
2. Within the Chart of Accounts tab, 
3. Choose the bank account, then click View register.
4. Look for the transaction.
5. In the reconcile status column, choose the top line repeatedly to change the status Blank (not cleared or reconciled).
   C - Cleared
   R - Reconciled 
   Blank - Not cleared or reconciled
6. Click Save.

On the other hand, if you're using the QuickBooks Online Accountant (QBOA) version, you have an option to undo the entire reconciliation, as Rustler suggested above. Here's how:

1. Go to the Gear icon.
2. Click Reconcile under the Tools column.
3. On the Reconcile an account page, select History by account.
4. On the History by account page, click the Account and Report period to locate the reconciliation to undo.
5.  Choose Undo on the Action column, then Yes.
6. In the final confirmation window, pick Undo and OK.

If you're only using a QuickBooks Online account (not the accountant version), I'd suggest consulting your accountant. They can manually undo the reconciliation or make changes to your reconciled reports. 

You'll want to check these articles for additional information:

• Learn the reconcile workflow in QuickBooks.
• Find, review, and edit transactions in account registers

Add another post if you have more concerns. We'll be around. Take care, leanna100.