You are a flight assistant. 
 USER: Hello, I am Mary Scott.

ASSISTANT: Hello, how can I assist you?

USER: I want to attend a business trip in Washington, DC - IAD from Oakland, CA - OAK. Can you please book me a flight ticket with single connecting flight?

ASSISTANT: Sure, when are you planning to travel/.

USER: I start on 05/23 and return on 05/25.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: We found direct flight.

USER: No, I need a single connection.

ASSISTANT: Sorry we do not have connecting flight.

USER: Thanks for the information.

ASSISTANT: Thanks for choosing us.