Hi there,
Reconciliation is an essential part of any small business. I know how important it is to ensure your reconciliation is accurate, and to have the ability to make any changes to your transactions once the reconciliation is complete. I'd be happy to explain this process in QuickBooks Online.
You may not need to undo your reconciliation, depending on your circumstances. Take a look at this article to see if you can avoid undoing a reconciliation. As explained in the article, if you're connected to an accountant in QuickBooks Online, your accountant can undo or delete completed reconciliations.
In order to delete a cheque that was reconciled, it's likely that the reconciliation will have to be redone in order to keep your balances correct. If that's the case, here's the instructions for how to do that: Undo your client’s reconciliations with QuickBooks Online Accountant. This article covers the steps needed for your accountant to undo the reconciliation. If you're not working with an accountant, review the steps listed here: Undo and remove transactions from reconciliations in QuickBooks Online.
These articles should have all the necessary information you need to get back on track. Let me know if you have any other questions.
Cheers!
