How To Fix WA161 - The existing subtype &1 is used for the extension

WA161 - Overview

• Message type: E = Error

• Message class: WA - Messages from Workflow Event Manager

• Message number: 161

• Message text: The existing subtype &1 is used for the extension

What causes this issue?

You want to extend an object type supplied by SAP by adding an event.
This is not possible. However, there is a subtype that can be extended.
This subtype is used for the remaining steps.
If there are several extendable subtypes, a delegation was entered for
the chosen subtype.

System Response

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

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

WA161 - Details

• Certainly! Here's a detailed explanation for the SAP error message WA161: The existing subtype &1 is used for the extension:
  
  Error Message
  WA161: The existing subtype &1 is used for the extension
  
  Cause
  This error occurs when you try to create or assign a new subtype in an extension structure or table, but the subtype you are trying to use already exists or is already assigned to another extension. In SAP, subtypes are used to differentiate between different extensions or variants of a structure or table. Each subtype must be unique within the context of the extension.
  In other words, the system detects that the subtype you want to use is already in use, and therefore it cannot be reused or duplicated.
  
  When does it occur?
  
  When creating or modifying an extension structure or table in the ABAP Dictionary (SE11).
  When trying to assign a subtype that is already assigned to another extension.
  When working with append structures or