You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Anna Johnson and I want to book a flight ticket to attend a workshop at DC-IAD from CA-SFO.

ASSISTANT: Ok may I know your travelling dates?

USER: My travelling dates are from 10/29 to 10/31.

ASSISTANT: Please hold on, I will check the availability and revert you.

USER: Ok.

ASSISTANT: Thanks for your time. Unfortunately there are no flights available for you according to your request.

USER: No issue. Thank you for your service.

ASSISTANT: Thank you for reaching us.