You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am planning to meet my school friends in Washington, can you please book the flight ticket from PHL to IAD?

ASSISTANT: Can you please share with us your trip dates?

USER: I want to take-off on 03/18 and return back from IAD on 03/20.

ASSISTANT: Please hold on a while.

USER: Sure.

ASSISTANT: To proceed further may I know your name?

USER: Sure, my name is Elizabeth Hall.

ASSISTANT: Sorry, no flights are available with your planning dates.

USER: Not an issue, anyway thank you for the information.

ASSISTANT: Thank you for reaching us.