You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Mark Martin here. I have to meet my nephew in Houston, could you book a flight ticket from PHX to HOU?

ASSISTANT: Sure, can you please share your travel dates?

USER: My trip dates are 07/07 and 07/09.

ASSISTANT: Let me check for the availability of flight.

USER: Sure.

ASSISTANT: Mark, I am sorry to inform you that there is no flight available at your requested dates.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for contacting us.