You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Christopher Thomas, I need to reserve a flight ticket to IAH from SFO.

ASSISTANT: May I know your travelling dates?

USER: Ok, my travelling dates are 12/09 and 12/11.

ASSISTANT: Sorry, no flights found on your preferable dates.

USER: Not a problem, anyway thank you for the information.

ASSISTANT: Thank you for reaching us.