The Undo option is available to accountants only under the QBOA edition. Until Intuit adds the option to the regular QBO edition, you have two options as a solution to this dilemma:
1. hire a real accountant to click the Undo button for you, or
2. "pretend" to start an accounting firm as a side business, sign up for QBOA trial under a different email address, and invite your brand new side business as an accountant to your primary business.
Log in at QBOA, and voila, you get the Undo option for your company's Reconciliation.
Sorry Intuit for all these phantom accounting firms, but you are asking for it. :-)
