You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Raymond Hernandez.

ASSISTANT: Do you need any help from my side?

USER: I want to travel from DFW to DEN. Can you help me to book a flight ticket?

ASSISTANT: Sure, can you please share your planned travel dates?

USER: I want to fly in the flight on Apr 27 and Apr 29.

ASSISTANT: Do you need an economy or business class flight?

USER: No, but I want to return in afternoon time.

ASSISTANT: Do you have any time preferences? Ok, please give me a moment.

USER: Ok, take your time.

ASSISTANT: I regret to say that no airline is providing a flight on your journey dates to book a flight ticket for you.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: It's my pleasure to help you and thank you for reaching us.