The Credit Delivery Agreements are used to reverse a closed Delivery Agreement and make the Trade Items available again.
Create a Credit Delivery Agreement
Find the Delivery Agreement to be credited and ensure that the status is equal to Closed and that it is linked to a Posted Sales Invoice. Then click General > Create a Credit Delivery Agreement. This action creates a credit delivery agreement and copies the information from the delivery agreement to it.
...
If so configured, then the returned trade items are reserved back to the original Delivery Agreement and the Delivery Agreement Lines regain their green and bold font. Alternatively the trade items are returned to free stock.
...