You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Mark Garcia. I would like to book a ticket to Charlotte, can you please help me out?

ASSISTANT: Sure, can you please share your source and destination airport codes?

USER: I am flying from IAH to CLT.

ASSISTANT: May I know your preferable dates to travel?

USER: I am travelling on these dates 06/16 and 06/18.

ASSISTANT: Please wait for a moment.

USER: Sure.

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

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

ASSISTANT: Thank you for approaching us.