You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you today?

USER: I am Karen Collins want to visit Washington, can you book a ticket from DTW to IAD?

ASSISTANT: Sure, please mention your journey dates.

USER: Sure, my travelling dates will be 10/30 and 11/01.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry Karen, there are no flight tickets available on your journey dates.

USER: That's ok, thank you.

ASSISTANT: Thank you for reaching our service.