You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I am Patrick Gonzalez here. I would like to book a flight ticket from Detroit. Could you please help me with booking a flight ticket from DTW to IAD?

ASSISTANT: Sure, I am happy to help you with that. Can you please share your preferable journey dates?

USER: My preferable journey dates are from 05/15 to 05/17.

ASSISTANT: Please wait for a minute.

USER: Sure, I will wait.

ASSISTANT: I am sorry to say that there is no flight found under your details.

USER: Not a big problem. anyway, thank you for the information.

ASSISTANT: Thank you for reaching us.