Hello there, neil31,
This will offset the created balance. Here's how:
- Click + New on the left pane.
- Select Receive payment or Receive invoice payment.
- Select the same customer you used for the check or expense.
- Fill out the other fields as you see fit.
- Under the Outstanding Transaction section, select the checkbox for the Expense or Check you created.
- Make sure the payment is equal to the open balance, then select Save and close.
Here's an article for more details: How to refund a deposit and close an invoice.
Let me know if you have other concerns.