Yes, it will changed @DEBW2020.

Once you change the account under the Product and Services, it will automatically update the transaction to the latest account set up.

You run can Transaction Journal report to see the accounts affected to every transaction you created. Here’s how:

1. Open a transaction.
2. Click More at the bottom.
3. Choose the Transaction journal.

To view important details of your finances and learn more about report features, you can always run a report in QuickBooks Online. 

If you have additional concerns, just let me know. I’m always here ready to help.