To delete the product from an existing sales invoice and add it back, please follow the below mentioned steps:
Step 1: Go to “Bills” >> Select Invoice.
Step 2: Click on “Edit”.
Step 3: Click on “Add/Edit” option.
Step 4: Delete the product by clicking on “Negative (-)” icon and add the product by clicking on “Positive (+)” icon >> Click on “Continue”.
Step 5: Click on “Update”.