Can I start all over in the middle of a bank reconciliation?

Hello there, @wobrien.

Yes, you can go back and start all over again if it happens that you didn't finish the entire bank reconciliation. 

Moreover, if you choose to click the Save for later button under the Finish now dropdown the time you're in the middle of the reconciliation. It will route you to the reconciliation page, from there you can click the  Start reconciling button for you to be able to reset all the transactions to their original session.

However, if you've already reconciled your bank, you can unreconciled it again and start over.

Here's how:

1. On the upper right corner, look for the Gear icon.
2. Select Chart of accounts.
3. Choose the account that has the reconciled transaction then click View register.
4. If the transaction is reconciled, choose it to expand the view.
5. In the checkmark column, click the box with the R until it's blank as this removes the transaction from the reconciliation.
6. Hit Save.

Furthermore, here's an article you can browse just in case you need assistance reviewing any discrepancies at the end of a reconciliation: Enter an adjusting entry for a reconciliation in QuickBooks Online.

If you still have any further queries, please know that I'm just one post away. I'd be glad to assist you again. Have a lovely day.