After you have raised a return order and emailed it to the vendor, you have to wait for the vendor to confirm the return.
To mark a return order as Returned
Navigate to Inventory > Procurement > Orders.
The Manage Purchase Orders & Transfers page is displayed.
Locate the order in Raised status.
Click the desired Ref#.
The return order is opened for editing.
The order is marked as returned and the stock level is reduced. The status of the is also changed to Delivered.
You can view the returned products in the Inventory > Reports > Returns report.