Extending Object Types: Inheritance and Delegation 
In particular situations you will need to modify an object type in conjunction with delegation rather than create a new object type. This applies whenever you want to add components to an object type which are not provided in the standard version and at the same time need to ensure that productive scenarios with the original SAP object type remain operational.
If no modifications are required, you can use any released object type provided by SAP as it is.
The procedure described below consisting of create subtype and delegation is always required when you have to extend an SAP object type to meet your requirements.
However, within this tutorial it is always assumed that the object type to be maintained did not exist in the Business Object Repository and therefore is created from scratch. This section therefore informs you about the procedure involved in certain extensions, but does not really belong to the tutorial.
Create a new object type as the subtype of the object type you want to extend. This subtype automatically inherits all the components (methods, attributes, and events) of the original object type including its implementation.
Choose .
In the field Object type, enter the object type you want to extend. This is then the supertype in the inheritance hierarchy.
Choose
Subtype.
For the new object type, enter:
A unique name that can be used to identify it
An object name
A name
A short description
Enter the name of the implementation program of the object type and assign the code letter of your application.
Confirm your entries with
and save the object type created as a local object or with package in a transport request.
Before you process "your" object type any further, define it as the delegation type of the supertype.
Exit maintenance of the object type and go back to the Business Object Builder. Choose .
Add a new entry to the table. To do this, choose , then .
Enter the name of the object type (supertype) for which you want to specify a delegation type.
Enter the name of the subtype as the delegation type.
Choose
.
The delegation entered is cross-client.
In all SAP Business Workflow definition tools, you still have to use the "old" object type (supertype). However, when the definition is read and evaluated (at runtime, for F4 input help, and so on), the definition of the delegation type (subtype) is used.