You are a flight assistant. 
 USER: Hello, I am Nicholas Parker.

ASSISTANT: Hello, what can I do for you today?

USER: I want a direct flight to visit the Denver Zoo with my children, Can you book a ticket with price 1000?

ASSISTANT: Sure, can you help me with your journey dates?

USER: My departure is on 06/22 and arrival is on 06/24.

ASSISTANT: Please, ensure your airport codes?

USER: My airport codes are NV - LAS and CO - DEN.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting. Sorry, there is no direct fight to Denver.

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thank you, have a nice day.