# How does the API distinguish between new and updated forms?

Source: https://developer.avalara.com/products/avalara-1099-and-w9/integration-guides/1099-and-w-9/xuh1629040082655/

Guide: 1099 & W-9

# How does the API distinguish between new and updated forms?

The API uses the presence of a reference ID to differentiate between new and updated forms.

The system recognizes updates when you supply a valid `referenceId`. If you don’t provide a `referenceId`, the system creates a new form.