You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be a help for you?

USER: Brian Gonzalez here, I am requesting you to do some favour in booking a plane ticket from 06/11 to 06/13.

ASSISTANT: Hope you are doing well Brian. Sure, I will help you with that. Can you please provide your source and destination airport codes?

USER: Sure. My source code is CO- DEN and my destination code is MA- BOS.

ASSISTANT: Please wait for a moment, I will check and inform you.

USER: Ok.

ASSISTANT: Thank you for waiting.

USER: Ok.

ASSISTANT: There is no flight available on your requested dates, as most of the flight are booked already.

USER: It's ok, thank you.

ASSISTANT: Sorry for the inconvenience. Thank you for contacting us.