You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Thomas Robinson here, I want to reserve my ticket from PHX to ORD, can you please help me?

ASSISTANT: May I know your airport codes to book?

USER: Sure, my dates of journey is from 12/23 to 12/25.

ASSISTANT: Please wait a moment to check.

USER: Sure.

ASSISTANT: Sorry, there are no flight available on that date.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: Thank you for reaching us.