Changing Purchase Orders 
You control how the system reacts to changes when an allocated purchase order is changed by making settings in Customizing under 
Logistics- General 
SAP Fashion Management Order Allocation Run (ARun) Cross-Applications Purchase Order Handling 
.
When you deallocate a purchase order, all allocated sales orders and stock transport orders are locked. If an order cannot be locked, the system generates an error message. The purchase order can only be processed when the locked order is unlocked.
Process
Deallocation Rule
In order allocation run Customizing for Purchase Order Handling, you can define deallocation rules to be used when purchase orders are changed. You can define a deallocation rule to deallocate or remove the previously allocated quantities
Requirement Date of a sales order and stock transport order: You can specify a requirement date for a sales order and STO based on the available options.
For example, if you choose Requested Delivery Date (VDATU) as a requirement date, the system considers the Item level requested delivery date of a sales order.
Future Stock Reference Dates: The From and To fields specify the range of days during which the deallocation should not occur.
When you change an existing allocated order and if the difference between the requirement date of a sales order or STO and the goods receipt date for a purchase order or confirmation is within the From and To field ranges, then the deallocation does not occur. If this difference does not fall within these field ranges, then the system behaves based on the values specified in the Date Reaction field check.
Field Checks: The system decides how and when the deallocation process should be triggered based on the following values specified in the field check:
D Deallocation Without Warnings: Order is deallocated completely without a warning.
W Warnings Before Deallocation: A warning message is displayed and the order is deallocated completely.
E Change Not Permitted: You cannot modify an order and deallocation is not possible.
For confirmations, the Restore checkbox determines whether assignments for a shipping notification are returned to the purchase order or deallocated.
Log Rule
The log rule determines the log file rule to be used for actions taken by the system during purchase order handling. You can define the log file rule in Customizing under Logistics - General SAP Fashion Management Order Allocation Run (ARun) Online ARun Log Maintain Log Rules .
You can use the log rule to determine which of the following exceptions should be considered in the log.
All messages
Only error messages
Only warning messages
Errors and warnings
Sort Rule
In ARun Customizing for purchase order handling, you can define how the system sorts requirements when it performs deallocation. You can use this sort rule to specify the order in which requirements are deallocated.
Assign Purchase Order Rules to Plants
You can also assign a deallocation rule, requirement sorting rule, and logging rule to a plant. You can do this in Customizing under Logistics - General SAP Fashion Management Order Allocation Run (ARun) Cross Applications Purchase Order Handling Assign Purchase Order Rules to Plants .