You are a flight assistant. 
 USER: Hello, I am Michael Hall.

ASSISTANT: Hello. How can I assist you today?

USER: Can you help me in booking a flight ticket from CA - SFO to DC - IAD?

ASSISTANT: Sure, may I know your preferable dates?

USER: I want to fly on 05/02 and return on 05/04.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry, no flights are available on your desired route.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for opting us.