You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Christopher Nelson.

ASSISTANT: In which way I can help you at this moment?

USER: I want to travel from JFK to SFO. Can you help me to book a flight ticket for me?

ASSISTANT: Sure, I can help you in booking flight ticket. Could you please mention your travel dates for booking flight ticket?

USER: I want to travel on 10/19 and 10/21.

ASSISTANT: Ok, please hold on a moment, I will check flight availability in this route.

USER: Ok, take your time.

ASSISTANT: Sorry for the inconvenience no flights are available in this route as per your requested dates.

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

ASSISTANT: Thank you for contacting us, have a nice day.