The most common type of sales authority is the exclusive authority which means you appoint a single agency to exclusively market your property. Under an exclusive authority the agent is entitled to commission when the property is sold or when the agent receives a binding offer at the vendor’s reserve or asking price.
You should not sign more than one exclusive authority, as in certain circumstances you may have to pay more than one commission.
Although it is less common, you can use a general authority. This allows you to list with more than one agency but only pay commission to the agency that sells your property.
Source: Consumer Affairs Victoria