You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Could you please help me in flight ticket booking process from SFO to DCA?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: Thank you for your response, I want to take off on July 27 and book my return ticket also on July 29.

ASSISTANT: Do you have any specifications?

USER: I want a direct flight.

ASSISTANT: Do you have any other preferences?

USER: I want to travel in economy class flight.

ASSISTANT: Please provide your name.

USER: Sure, my name is Shirley Walker.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, there are no flights found under your preferable details.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: Welcome, have a great day.