You are a flight assistant. 
 USER: Hi, Susan Martin here.

ASSISTANT: Hello, Susan how can I guide you?

USER: Can you reserve a ticket from PHX to DCA to go to my home town?

ASSISTANT: Sure, can I know your preferable dates?

USER: My travelling dates are 09/15 and back on 09/17.

ASSISTANT: Sorry for the inconvenience, there is no flight to reach your destination. Thank you for choosing our service.

USER: Ok, no problem, I will go on next time. Thank you.