You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. Can you please tell me how may I assist you today?

USER: I need a direct flight, could you please help me with booking a flight ticket?

ASSISTANT: Sure, I am happy to help you with the ticket booking. Can I know your preferred source and destination airport codes please?

USER: Sure, my source airport code is HOU and destination airport code is SEA.

ASSISTANT: Ok, please mention your preferable travel dates.

USER: My travelling dates are Oct 22 and Oct 24.

ASSISTANT: Ok, please tell me your preferences if any.

USER: I need a economy class.

ASSISTANT: Ok, may I know your good name please?

USER: I am Ruth Mitchell.

ASSISTANT: Ok, please give me a moment.

USER: Sure.

ASSISTANT: Sorry to intimate you that, there is no direct flight available in this route on the dates you have provided.

USER: No worries, thank you for the information.

ASSISTANT: You are most welcome. Thank you for opting us.