In a bot, everything begins with the root dialog. The root dialog invokes the new order dialog. At that point, the new order dialog takes control of the conversation and remains in control until it either closes or invokes other dialogs, such as the product search dialog. If the new order dialog closes, control of the conversation is returned back to the root dialog.
According to this study by Petter Bae Brandtzaeg, “the real buzz about this technology did not start before the spring of 2016. Two reasons for the sudden and renewed interest in chatbots were [number one] massive advances in artificial intelligence (AI) and a major usage shift from online social networksto mobile messaging applications such as Facebook Messenger, Telegram, Slack, Kik, and Viber.”
[In] artificial intelligence ... machines are made to behave in wondrous ways, often sufficient to dazzle even the most experienced observer. But once a particular program is unmasked, once its inner workings are explained ... its magic crumbles away; it stands revealed as a mere collection of procedures ... The observer says to himself "I could have written that". With that thought he moves the program in question from the shelf marked "intelligent", to that reserved for curios ... The object of this paper is to cause just such a re-evaluation of the program about to be "explained". Few programs ever needed it more.[8]