You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you aid me to book a flight ticket from ORD to HOU?

ASSISTANT: Sure, may I know your trip dates please?

USER: My trip dates are Apr 27 and Apr 29 respectively.

ASSISTANT: Do you have any other requirements?

USER: I prefer for direct flight and return time in morning.

ASSISTANT: Can I know your name please?

USER: Ryan Roberts here.

ASSISTANT: Ok, please wait.

USER: Ok.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: Thank you.

ASSISTANT: Most welcome.