You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I want to book a flight ticket from IAD to LAX to meet my grand parents and spend time with them.

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

USER: Sure, my travelling dates are July 29 and July 31.

ASSISTANT: Do you have any preferences about flight connections?

USER: No, I comfortable with any connection.

ASSISTANT: Do you have any preferences about class?

USER: No.

ASSISTANT: Please mention your name.

USER: I am Paul Allen.

ASSISTANT: There are no flights found under your preferable details.

USER: No worries, thank you for the information.

ASSISTANT: Welcome, have a great day.