You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you?

USER: I want to visit waterfalls located in San Francisco. Can you book a ticket from IAD to SFO?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My planned travel dates are 03/13 and 03/15.

ASSISTANT: Do you have any preferences?

USER: I want a flight with single connection.

ASSISTANT: May I know your name please?

USER: Sure, Carolyn Scott here.

ASSISTANT: Sorry, there is no flight available with your requirements.

USER: No issues, thank you for the information.

ASSISTANT: You are welcome, have a nice day.