Hello, wschulman300. I understand the importance of correcting the date of your account reconciliation in QuickBooks Online (QBO). We can work together to sort this out.
Since you finished the reconciliation process, you need to undo the reconciliation and correct the year date.
You can manually undo the reconciliation or invite an accountant to undo the entire reconciliation for you. They can undo the entire period at once using QuickBooks Online Accountant.
To invite your accountant:
Click the Gear icon in the upper-right corner, and select Manage Users.
Go to the Accounting firms tab, and click the Invite button.