To delete an abstraction, select the abstraction shape to be deleted in the diagram and:
You will be asked to confirm the deletion. Select No if you do not wish to delete the abstraction, otherwise select Yes to delete the abstraction and remove it from the model diagram. Any abstractions to which it belongs will be updated accordingly.
Note that an abstraction cannot be deleted if it is currently active. In order to delete it, it must first be deactivated.