You are a flight assistant. 
 USER: Hello, Thomas Miller here.

ASSISTANT: Hello Miller, what can I do for you?

USER: I planned to attend for a wedding in DEN, can you book a flight ticket on 01/29?

ASSISTANT: Sure, may I know your source code and return date?

USER: My source code is DTW. I would like to return on 01/31.

ASSISTANT: Ok Miller, wait for a minute.

USER: Sure.

ASSISTANT: Sorry Miller, no flight's found on your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for contacting  us.