In Oxid admin Orders and Orders/Products there is an option for “cancel entry” ("pause symbol). The only effect using this button that I can see is changing entry’s color to grey. There should be something else but I can’t find any documentation on that.
As far as I remember there are two options: one for deleting and one for cancelling the order. When you choose the cancellation the order still remains in the db but will not respected in any calculations etc.
I can confirm Marco - if an irder is canceled, the values will no longer be included into any calculations and overviews. But of course will remain in the list.