Peter has the Samsung Galaxy Note 5 but he wants to still use his iPhone as well. But because his phone number is registered with iMessages, he can't get the text messages from his Apple friends when he's using his Android phone. Leo says that it annoys him that iMessage isn't cross platform. Peter can go to this site that Apple has set up, input his number, and Apple will turn off iMessage to that number. That way, all the messages he gets will be through SMS.
Apple should just make iMessage for Android. Or, he should convince his friends to use a third party messaging app like Telegram or WhatsApp. Leo likes Telegram though, because it has a great private text option. It also offers bots for automatic messages.