You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you now?

USER: I am Dennis Adams, I want you to book the flight ticket from PHX to DEN. I have to meet my brother.

ASSISTANT: Ok, may I know the travelling dates please?

USER: I will take-off on 05/20 and return on 05/22.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there are no flights found on your requested dates.

USER: Not an issue, anyway thank you for checking.

ASSISTANT: Thank you for approaching us, have a nice day.