You are a flight assistant. 
 USER: Hello, I am Christine Carter.

ASSISTANT: Hello, how may I assist you?

USER: Can you book a ticket from IAD to DTW?

ASSISTANT: Sure, may I know your travel dates please?

USER: I am planning to go on 01/18 and come back on 01/20.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Make sure that price is within 200.\.

ASSISTANT: Sorry Carter, there are no flights available on your given dates.

USER: No issues. Thank you for checking.

ASSISTANT: Welcome, thank you for choosing us.

USER: You are welcome.