You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you out?

USER: Can you book a flight ticket from HOU to IAH to attend my sister's marriage?

ASSISTANT: Sure, I am happy to help you. Let me know your trip dates.

USER: Oct, 26 and Oct, 28 are my planned travel dates.

ASSISTANT: Do you prefer any stopover in between journey?

USER: No, I need direct flight.

ASSISTANT: Please help me with your class preference.

USER: I am comfortable with any class.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: May I know your good name?

USER: Ryan Turner here.

ASSISTANT: Thanks for providing details, no flights are available on your journey routes.

USER: That's ok, no worries.

ASSISTANT: Thank you for opting us.

USER: Thank you.