You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Patrick Campbell here.

ASSISTANT: How can I help you?

USER: I want to attend a Seminar in Houston. Can you please help me for booking the flight ticket?

ASSISTANT: Let me know your travelling dates.

USER: My travelling dates are 07/27 and 07/29.

ASSISTANT: Can I know your airport codes?

USER: Sure, I want to travel from SEA to HOU.

ASSISTANT: Do you have any preference?

USER: I would like to return in afternoon time.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: Oh! Sad to hear that. Anyway, thank you for the information.

ASSISTANT: Thank you.

USER: Welcome.