reconcile date is wrong

I'll guide you in fixing a reconciliation date in QuickBooks Online (QBO), @phochstuhl.

When your reconciliation is done, you can no longer change the statement ending date or year. You can leave it as is since an incorrect date/year doesn't affect any balances and won't prevent you from doing your future reconciliation.

However, if you wish to correct the date/year, you can either let your accountant (using QuickBooks Online for Accountant version) undo the reconciliation for you or manually remove the transactions from the completed reconciliation (for the regular QBO version).

To manually unreconcile an individual transaction from reconciliations in QBO, here's how:

1. Go to the Accounting menu.
2. Select the Chart of accounts tab.
3. Find the account that has the reconciled transaction. Then select View register.
4. Find the transaction. If it's reconciled, you’ll see an “R” in the checkmark ✔ column.
5. Select the transaction to expand the view.
6. In the checkmark ✔ column, select the box with the “R” until the box is blank. This removes the transaction from the reconciliation.
7. Select Save. 
8. Close the account register.

Once everything is set, go back to the Accounting menu and reconcile your account with the correct year (2021). You can also refer to this article for the step-by-step guide: Reconcile an account in QuickBooks Online.

Also, to further guide you in doing or fixing a reconciliation in QBO, I'd recommend checking out this article: Learn the reconcile workflow in QuickBooks.

Keep me posted in the comments if you have other reconciliation concerns and questions about managing transactions in QBO. I'm always ready to help. Take care, and I wish you continued success, @phochstuhl.