You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I am Ryan Martinez. I would like to book a ticket to Houston, can you please help me out?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: I am travelling on these dates 08/12 and 08/14.

ASSISTANT: Can you please share your source and destination airport codes?

USER: I am flying from LAS to HOU.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: Ok no problem, thank you for your services.

ASSISTANT: Thank you for contacting us.