You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jacob Jackson.

ASSISTANT: How can I assist you today?

USER: Can you please help me to book a flight ticket from JFK to DCA?

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

USER: My journey dates are Dec 14 to Dec 16.

ASSISTANT: Do you have any specifications?

USER: I want to return in the evening.

ASSISTANT: Do you have any other preferences?

USER: I need a flight with single connection.

ASSISTANT: Please give me a moment.

USER: Sure.

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

USER: No problem, thanks for your information.

ASSISTANT: Welcome, have a great day.