How do I fix an ending date on a reconciled statement from a year ago?

Hi there, @skw51565.

I'm happy to see you here. I'm here to help you correct the ending date on your reconciled statement for September 2021 to ensure proper recordkeeping.

The option to change previous reconciliations' statement ending date is unavailable. To fix it, you may un-reconcile the individual transactions in that period. Then,

Here's how:

1. Go to the Accounting menu, then Chart of Accounts. 
2. Find the account you're working on. Then, click View register.
3. Locate the transactions. If the transaction is reconciled, you’ll see an “R” in the checkmark ✔ column.
4. Select the transaction to expand the view.
5. In the checkmark ✔ column, select the box with the “R” until the box is blank. This removes the transaction from the reconciliation.
6. Select Save.

Once done, go back to the Accounting menu and reconcile your account with the correct statement date.

Just in case you encounter any issues while reconciling, you can check out this article to learn fixing it: Fix issues at the end of reconciliation in QuickBooks Online. 

I'd love to hear how these steps go. I'll be around if you need further assistance with the process. Have a great day!