I came with a video about GR process with Inbound Delivery in SAP Warehouse Management. I hope it will be useful for your learning. Watch the video and give your valuable comments.
I got an idea to prepare this document as per the flow of tickets in one of the support projects I worked. When user wants to reverse the entire quantity of the previous document which he/she has posted earlier can be done easily with the help of Transaction code MBST or Cancellation option in MIGO. But when he/she wants to perform partial reverse, it would be a task which needs some manual effort. Although it is not that much critical activity, I felt this document will be helpful to handle this successfully