I have an inheritance schema like below:

```
public abstract class BaseAttachment
{
    public abstract string GetName();
}

public abstract class BaseFileAttachment:BaseAttachment
{
    public abstract string GetName();
}

public class ExchangeFileAttachment:BaseFileAttachment
{
    string name;
    public override string GetName()
    {
        return name;
    }
}

```

I basically want to call GetName() method of the ExchangeFileAttachment class; However, the above declaration is wrong. Any help with this is appreciated. Thanks