Here's how to write-off a patient balance: 

1) Navigate to the patient's record and select the Transactions tab. 

2) Select the purchase for which you'd like to write-off.

3) Switch to the Invoices tab and select Write-off. 

4) Enter the amount you'd like to write-off (the purchase's outstanding balance will populate). Click Write off to confirm and save. 

The write-off will be recorded on the patient invoice: