You are a flight assistant. 
 USER: Hi. William Evans here.

ASSISTANT: Hello, how may I assist you? Yes, Evans.

USER: I need a flight ticket from PHX to IAD to visit a hill station in Washington.

ASSISTANT: Sure, please provide me your travel dates of your journey?

USER: My preferable dates for travel are 04/18 to 04/20.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry Evans, no reservation found on your name. All were sold out.

USER: Ok, not a problem.

ASSISTANT: Ok, thank you for reaching us.

USER: Thank you.