You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Justin Brown.

ASSISTANT: How can I aid you today?

USER: I need to go San Francisco to attend a business meeting there so please help me with flight ticket booking from DCA to SFO.

ASSISTANT: Sure, please provide your journey dates.

USER: Thank you. I would like to travel on dates of Mar 23 and Mar 25.

ASSISTANT: Ok, do you have any preferences?

USER: Yes, I need connection 1 but direct flight is also fine with me.

ASSISTANT: Ok, please wait for a while.

USER: Sure, take your time.

ASSISTANT: Sorry, we could't found any flights for you.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you for reaching us.

USER: Most welcome.