You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you?

USER: My name is Virginia Brown. Can you help me to book a flight ticket from IAD to SFO?

ASSISTANT: Ok, may I know your travelling dates?

USER: Ok, my itinerary dates are from 02/10 to 02/12.

ASSISTANT: Sorry, no flights found on your preferable dates.

USER: No problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.