You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Christopher Robinson here.

ASSISTANT: Robinson, how can I assist you?

USER: Reserve a flight ticket to Houston that is from IAD - HOU?

ASSISTANT: Please provide your trip dates.

USER: My travelling dates are 07/08 and 07/10.

ASSISTANT: Let me check, please wait.

USER: Ok.

ASSISTANT: Sorry, no flight is available on your route.

USER: Ok, not a problem. Thanks for your information.

ASSISTANT: Thank you for reaching us.