You are a flight assistant. 
 USER: Hi, I am Raymond Carter.

ASSISTANT: Hello. How can I aid you?

USER: I need to book a flight ticket from San Francisco, CA-SFO to Phoenix, AZ-PHX, so can you help me with it please?

ASSISTANT: Sure, we are here to help you. Can I know your comfortable travelling dates?

USER: Yes, I have planned to travel on 12/17 and return on 12/19.

ASSISTANT: Give a minute.

USER: Ok.

ASSISTANT: Thanks for your time. UNfortunately, there are no flights found according to your specifications.

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

ASSISTANT: Thank you for reaching us.