It may sometimes be necessary to cancel an existing posting (due to errors entering data, for example). In RIS, this results in a reduction in the key figure affected.
The following processes reduce the original key figure:

A good receipt is without a previous purchase order is posted with an external vendor (movement type 501). If the article document is cancelled or a goods receipt is posted with the cancellation movement type 502, the key figure "Goods receipt (external vendor)" in RIS is reduced.
Any changes to conditions that are made while you are using the cancellation movement type will result in incorrect value reductions in RIS. In cases such as this, you must cancel the material document.

Physical return deliveries must never be performed using a cancellation movement type, as this reduces key figures (such as Goods Receipt) without updating the complementary key figures (such as Returns).