Design Pattern name for Delegate + Partial Override

I found myself dumbstruck trying to name a class with the following characteristics :

Let's say the Business interface defines two complex operations:

interface Service {
  void doSomething();
  void doSomethingElse();
}

A third party provided an implementation that is partially correct :

final class DefaultService implements Service {
    void doSomething() { 
        // OK
    }

    void doSomethingElse() {
        // KO
    }
}

Since extension is not an option, I created a class that delegates to DefaultService the correct doSomething() method, and has its own implementation of doSomethingElse() :

final class IDontKnowTheName implements Service {

    private DefaultService delegate;

    void doSomething() { 
        delegate.doSomething();
    }

    void doSomethingElse() {
        // Roll new implementation here
    }
}

Is there a name for an "overriding/delegating" class ?

• Not an Adapter since the original class DefaultService already implemented the Service interface
• Not a Delegate because a method is overridden
• Not really a Decorator either because some functionality of the target class is replaced, not enhanced