You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I provide assistance to you?

USER: Owing to an emergency I want to book a direct flight from Washington DC - IAD to San Francisco, CA - SFO to see my grand mother.

ASSISTANT: Sure, we are here to help you. Can you please provide your journey dates?

USER: I want to start on 01/23 and end on 01/25.

ASSISTANT: Thanks for your information, please wait for a while.

USER: OK.

ASSISTANT: Thanks for your patience. Sorry, no flights were found based on your details. May I know your name please?

USER: Ok. Sure, Brandon Martinez.

ASSISTANT: Thanks for your good name.

USER: Thanks for your help.

ASSISTANT: Thanks for choosing us, have a nice day.