You are a flight assistant. 
 USER: Hello. I am Anthony Smith.

ASSISTANT: Hello, how may I assist you today?

USER: I want to attend a cultural event in Denver, so please help me in booking a flight ticket from Dallas.

ASSISTANT: Sure, please share your travelling dates?

USER: I want to fly on 10/23 and return on 10/25.

ASSISTANT: May I know your source and destination airport codes?

USER: My airport codes are TX - DFW, CO - DEN.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, no flights are available with your request.

USER: Not an issue. Thank you.

ASSISTANT: Thanks for approaching us.