Hi there, @usercthuss33.
Once you finish reconciling your account, changing the Ending date will be unavailable in QuickBooks Online (QBO). This is the reason why you're unable to see any edit option in the History by account window.
However, you can still correct the Ending date by undoing the entire reconciliation. Then, you can reconcile it again and close your books. Please take note that you can only perform this action one at a time.
If you have an accountant that uses QuickBooks, you can also reach out them. This way, they can use their tools that can undo the entire reconciliation.
In addition, you can check our reconciliation workflow in QuickBooks. You can use this as guide in case you need help in fixing a reconciliation.
I'm always here to help if you have any other concerns or questions. Just tag my name in the comment section and I'll get back to you as soon as I can.