To return purchased goods, open the purchase details and click on the Return Goods option in the menu. 
Goods can be returned only for approved purchase orders. It's possible to return only some of the goods. In that case the original purchase order can be returned again, until all goods are returned.
This creates a return document with negative quantities:
- Define the returned goods quantity for each product variant in negative values.
- The amount value will be calculated automatically according to the defined returned quantity.
- Additional items cannot be added to a return document.
- The total value will be calculated automatically according to the defined returned items.
- Click on [SAVE] button or press F9 keyboard key to save the changes, or click on the [CANCEL] button to ignore the changes.
Link to the original document is visible at the bottom of the invoice Details/Edit page.