Even with the drawer at a negative cash amount, you will need to manually enter it like you would enter a positive cash amount when closing your drawer.
  1. On the Sales tab, click Approve Closed Drawers
  2. Click the drop-down next to the drawer that only has the refund and click Edit
  3. In the "Cash in drawer" section, click Hide Calculator
  4. Enter the amount with parenthesis around it to show a negative amount. Ex: ($5.00)
  5. Save