Inbound Delivery 
There are two possible scenarios in which the stock-specific unit of measure (SUoM) can be used in the inbound delivery process:
The purchase order and inbound delivery in ERP are entered using the SUoM. The SUoM is set by the vendor in the advanced shipping notification. After replication, the inbound delivery uses the SUoM.
The purchase order and inbound delivery are in base UoM in ERP and the SUoM is set in EWM. It can be be set automatically if a preferred UoM is specified in the product master, or it can be modified manually. For more information, see Preferred Unit of Measure in Inbound Delivery.
You can also enter or change the alternative unit of measure (AUoM) during the inbound process at the following points:
Before goods receipt (GR)
During expected GR and receipt of handling units
During packing or deconsolidation
During putaway confirmation