You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Timothy Roberts. I would like to book a ticket from Atlanta-ATL to Oakland-OAK to meet my family members.

ASSISTANT: Sure, may I know your travelling dates?

USER: I am departing on 01/15 and return on 01/17.

ASSISTANT: Give me  a minute.

USER: Sure, take your time.

ASSISTANT: I feel gloomy to say this, there is no flight on your preferable dates.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us.