If an app hasn't been published I don't think you can delete it from your account. Also, I think you'll have to change both the app name & the package name because Apple doesn't allow duplicates of either. Duplicate package names aren't allowed for obvious reasons, but I'm not sure why they don't allow duplicate app names like Play Store does.
Also - it used to be that even if you deleted an app, you still couldn't re-use the name (not sure about the package name). I don't know if that's still the case.
You might be able to get around the name/package name issue by transferring ownership of the app to the organization account.
- Colin.