You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Is there any availability of flights for booking a flight ticket from LAS to DTW ?

ASSISTANT: Let me know your travelling dates.

USER: My trip dates are on May 25 and 27.

ASSISTANT: Is there any airline preference?

USER: I am fine with any airline.

ASSISTANT: Do you have any class preference?

USER: I am comfortable with any class.

ASSISTANT: Can I know your name?

USER: Dennis Baker is my name.

ASSISTANT: Sorry, no flights found for your travelling dates.

USER: Ok, thanks for your assistance.

ASSISTANT: Thank you.