You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How exactly I can serve you the best today?

USER: I need a direct flight from Las Vegas to attend emergency surgery, can you please do the reservation for me?

ASSISTANT: Sure, On which dates would you like me to book a flight ticket for you?

USER: My journey dates are, depart on Dec 15th and arrival on 17th.

ASSISTANT: I need your selected airport code, that you wish to land at?

USER: My destination airport code is HOU.

ASSISTANT: Is there any other specifications regarding your journey?

USER: I don't have any other specifications.

ASSISTANT: May I know your good name please?

USER: My name is Daniel Brown.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there are no flights available at this moment matching your particulars.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for approaching us, wish you a great day.