Can someone please tell me how to unreconcile an account, I put the wrong month end date?

It's good to have you here, Johe.

I'll provide steps on how to undo reconciliation so you can enter the correct month-end date.

There are two ways to undo the reconciliation. The first one is to perform it in batches; only the accountant can do so. The second one is to manually undo the reconciliation so you can correct the end date.

Feel free to follow these steps for an accountant:

1. From the Accounting menu, select the Reconcile tab.
2. Click History by account. Then, choose the account to undo the reconciliation and date range from the dropdowns.
3. Look for the reconciliation on the list. Select View report to open the Reconciliation Report.
4. Review any discrepancies and changes the client wants to make. Once ready, click the dropdown icon in the Action column, then Undo.
5. Tap Yes and Undo to confirm.

For more info, you can read this article: Undo a client’s reconciliation in QuickBooks Online Accountant.

Then, to manually undo the reconciliation, you can follow these steps:

1. Select the Chart of accounts from the Settings section.
2. Look for the account you've reconciled. Then, View register. 
3. Find the transactions. You'll see an "R" if it's reconciled in the checkmark column. Click the transaction to expand. 
4. Then, move the cursor to the "R" icon and tap it until the box is blank to remove reconciliation. Perform this to all reconciled transactions in that account.
5. Once done, click Save. Then, close the account register.

Check out this article for more info: Undo or remove transactions from reconciliations in QuickBooks Online.

Also, you can read this article if you see a small amount left over after reconciliation: Enter an adjusting entry for a reconciliation in QuickBooks Online.

For additional questions about correcting your reconciliations, you can come back here. We'll be willing to help. Keep safe, and have a good one.