You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER:  I want to book a flight ticket for my two days trip from 03/09 to 03/11, can you help me?

ASSISTANT: May I know your desired airport codes please?

USER: Ok, my source and destination airport codes are DTW to DEN.

ASSISTANT: Please wait a while.

USER: Ok, take your time.

ASSISTANT: May I know your name please?

USER: My name is Samuel Miller.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

USER: Ok, no problem.

ASSISTANT: Thank you for opting us.

USER: Thank you for your response.