You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am Lisa Gonzalez. I need to book a flight from DEN to DTW.

ASSISTANT: Please share your trip dates.

USER: My preferable dates are from 01/29 to 01/31.

ASSISTANT: Please hold on for a while.

USER: Ok, take your time.

ASSISTANT: Sorry, no flight is available on your route.

USER: Ok, no problem. Thank you for helping me.

ASSISTANT: Thank you for choosing us.