You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I guide you?

USER: Charles Clark here.

ASSISTANT: Ok.

USER: I need your help in booking a flight ticket from my home town Houston. Can you please help me in that?

ASSISTANT: Sure, can I know your preferable dates?

USER: I want to start on 11/30 and return back on 12/02.

ASSISTANT: Ok, can I know your airport codes?

USER: My source and destination codes are IAH and DTW.

ASSISTANT: I am sorry, there are no flights available.

USER: Ok, no problem.

ASSISTANT: Thank you, have a good day.

USER: Thank you for your information.