How To Fix ACO400 - Substitutes for '&1' are being changed by &2

ACO400 - Overview

• Message type: E = Error

• Message class: ACO - Error Messages for Package ACO

• Message number: 400

• Message text: Substitutes for '&1' are being changed by &2

What causes this issue?

You want to enter substitutes for '&V1&', but this data is currently
being changed by &V2&.

System Response

The system does not allow you to enter substitutes for '&V1&'.

How to fix this error?

Try and enter the substitutes for '&V1&' again, later on.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message ACO400 - Substitutes for '&1' are being changed by &2 ?

  The SAP error message ACO400 indicates that there is a conflict or issue with the substitution of a specific item (represented by &1) that is being modified by another item (represented by &2). This typically occurs in the context of material management, where substitutions are used to replace one material with another in various processes, such as sales orders, production orders, or inventory management.
  
  Cause:
  
  Substitution Configuration: The error may arise from the configuration of substitution rules in the system. If multiple substitution rules are defined for the same material, it can lead to conflicts.
  Data Inconsistency: There may be inconsistencies in the master data for the materials involved, such as incorrect or missing information in the material master records.
  User Actions: The error can also occur if a user attempts to change a substitution while another process is already modifying it.
  
  
  Solution:
  
  Review Substitution Rules: Check the substitution rules defined in the system for the