You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Amy Hernandez. I need to book a flight ticket from DTW to IAD, Can you please help me for booking?

ASSISTANT: Sure, tell me your travel dates please?

USER: I would like to travel on 03/21 to return on 03/23.

ASSISTANT: Please wait. Thanks for waiting. But I am sorry to say that there are no flights available.

USER: That's not a problem. Thanks for your information.

ASSISTANT: Thank you.