Hi there, @4003.
I'd be glad to help share information about reconciling transactions in QuickBooks Online (QBO).
Once you've reconciled your transactions on one of your accounts in the Chart of Accounts, any changes made to the transaction or any reconciliation after the reconciliation period wouldn't be included on the report. However, the reconciled transaction/s, will affect on the opening balance of the current period.
You can see attached screenshots for additional reference.
On the other hand, to learn more about reconciliation and reconciling transactions in QBO, you may check these articles:
I'll be right here to help you if you have any other reconciliation questions, just add a post/comment below. Have a great day ahead!