For example to reduce the qty to match the fulfilled (Reason for this if the qty is higher than the fulfilled this causes the item to keep going to back order. The qty and fulfilled must match)
I have reduced the qty to 1 now.
The reason this could not be amended was due to you have to amend the WOS61666
To find this you will have to click on the three dots ...
Scroll down to Linked to document number
This will tell you what the linked document number is
On the search bar type in WOS61666 (Do Not press enter on search) let it drop down some search items. Then click on edit
Reduce the qty to 1 tab out and ok
Also you will have to remove the unique line key by scrolling right a bit. The one I removed for this was 31739043 (ALWAYS KEEP A NOTE OF THIS. In case something happens we can refer to this) Tab out and okay
Then click on save
Go back to the sales order
Edit the sales order and reduce the qty to 1
Then click save