You can decrease the quantity of a dispensed medication of an invoice line item and the quantity of the source prescription at the same time. To decrease the quantities, you must first disable the source medication record. Then you must make a medication record that has the decreased quantity.

1. Open the applicable invoice.
2. Double-click the Clinical Record (optional) box.
   
   ezyVet shows the source clinical record in a record tab.
3. Find the applicable medication record.
   
4. Select the red cross button of the medication record.
   
   ezyVet shows an Are You Sure? pop-up window.
5. Select Disable.
   
   ezyVet shows a confirmation message:
   
   
6. Adjacent to Medication, select the plus button.
   
   ezyVet shows the Medication Prescription dialog box.
7. In the Drug box, select the applicable medication.
   
8. In the Qty box, enter the decreased quantity.
   
9. Make the other settings as necessary.
10. Select Add + Dispense.
    

ezyVet automatically makes the change in the initial invoice. The applicable invoice line item shows the changed quantity of the dispensed medication: