You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How may I help you?

USER: I am Catherine Walker and I want to book a flight ticket.

ASSISTANT: Sure, Can you provide me the journey details?

USER: I would like to fly from Denver, CO - DEN to Los Angeles, CA - LAX.

ASSISTANT: OK, On which date would you like to travel?

USER: My departure day to be on Sept/30 and return day to be on Oct/02.

ASSISTANT: Please wait for a moment, I will check and inform you the availability of the flight.

USER: OK.

ASSISTANT: Thanks for being patient, Unfortunately we did not find flights with your requirement.

USER: OK, thank you.

ASSISTANT: Thank you for contacting us, Have a great day.