How do I re-open a reconciled account that I closed thinking I could go work on the next month?

Hi there, I'm here to help you open a reconciled account to get to working order in QuickBooks Online (QBO).

To clarify, when you say "reconciled account that I closed" are you referring to the closed account via the Close the books feature? If so, you can just turn this off and reconcile that account again. Here's how:

1. In your QBO account, select the Gear icon and click the Accounts and settings menu.
2. Then, select Advanced and click the Accounting section.
3. From there turn off the Close the books feature. 
4. Click Save and then, select Done.

After that, you can now proceed in reconciling your account. For more details, check out this article: Close your books in QuickBooks Online.

On the other hand, if you're referring to re-opening the reconciled transactions, the option to batch undo them is unavailable (QuickBooks Online Accountant users can perform this action). You'll have to unreconcile them manually. To do so, follow Step 2 of this article: Undo or remove transactions from reconciliations in QuickBooks Online. 

Once ready, reconcile the account again. 

After the reconciliation, the program will automatically generate a report for this session. You can use this as a reference to avoid mistakes in future reconciliation: How do I view, print, or export a reconciliation report?.

If you have any other concerns managing your accounts in QBO, please don't hesitate to leave a reply below. Have a good one and stay safe.