The Answer Phone service provided by Orange is a popular feature--popular, in large part, because few people know how to disable it. As it turns out, you can't do it yourself. There are no menu settings for it, so there's no way to do it just by fiddling with the menus on your phone.
Find the number of your local Orange phone service provider. You can generally find this number on your bill or online.
Call the number, and follow the menu prompts until you get to speak with a live Orange operator.
Tell the operator you wish to disable Answer Phone.
When you want to reactivate Answer Phone, call that number again and follow the same procedure. This time, of course, tell the operator you want to restore that service.
When you disable Answer Phone, you will obviously lose access to that feature -- including the ability to listen to your voicemail messages from just about any phone.