You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Brian White.

ASSISTANT: How may I guide you today?

USER: I am planning to visit Museum of Nature and Science at Denver, could you please help me with booking a flight ticket from PHX to DEN?

ASSISTANT: Sure, I will help you with that. Can you please share your preferable journey dates?

USER: I would like to take off on 03/18 and return on 03/20.

ASSISTANT: Please wait for a minute.

USER: Sure, take your time.

ASSISTANT: I am sorry to say that there is no flight found under your details.

USER: That's ok, I will find an another alternate way to complete my trip.

ASSISTANT: Thank you for contacting us.

USER: Anyways, thank you for the information.