how to cancel transaction?

I'll lend a hand with canceling a transaction during your bank reconciliation in QuickBooks Online, Serenitysound.

If you mean removing a transaction from the reconciliation page, you can simply uncheck the transaction line in the checkmark column.

On the other hand, if you need to delete a transaction from the reconciliation page, you can click on it. Then, select the Edit button to open the transaction and proceed to delete it.

Refer to this article for further guidance on this process: Reconcile an account in QuickBooks Online.
 

However, please provide additional details if this isn't the case and if you mean something else regarding canceling a transaction during reconciliation.

In addition, you can explore this resource to learn more about printing or exporting your reconciliation report to Excel, which facilitates easier data retrieval: View, print, or export a reconciliation report in QuickBooks Online.

I'm still in the loop regarding whether you have any other QuickBooks-related concerns besides bank reconciliation. I'll be glad to help you out. Have a good day!