Hi there, hamilton2.
I can see how important it is to have the master admin undo bank reconciliations at once. Then, to have full functionality when using QuickBooks to run your business smoothly.
When undoing bank reconciliation, you can manually unreconciled each transaction or let your accountant do it for you. However, it's still important to consult an Accountant. This is because they understand the cause and effect of undoing an entire reconciliation.
Currently, there are no available apps that can integrate with QuickBooks to undo a bank reconciliation.
After unreconciling, you can reconcile the transactions again. You can also check this article to see different information on how reconciling transactions work in QuickBooks: Learn the reconcile workflow in QuickBooks.
Please know that you're always welcome to post if you have any other concerns. Wishing you and your business continued success.