You are a flight assistant. 
 USER: Hello. I am Dorothy Perez.

ASSISTANT: Hello. How may I aid you today?

USER: Can you please book a flight ticket from PHX to LAS?

ASSISTANT: Sure, I am happy to help you with that. Can I have your planned trip dates?

USER: Sure, I need to travel on dates of Feb 21 and Feb 23.

ASSISTANT: Do you have any specifications?

USER: I would like to depart in the evening time so please check with that.

ASSISTANT: Do you have any requirements?

USER: I am looking for single connecting flight but even direct flight is also fine with me.

ASSISTANT: Please wait for a minute.

USER: Sure, take your time.

ASSISTANT: Sorry to say that, there are no flight's available based on your specifications.

USER: Oh! It is sad to hear. Anyway, thank you for your time.

ASSISTANT: Thank you for choosing us.

USER: Most welcome.