You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you now?

USER: I am planning to book a ticket from LAS to MCO, can you please help me out?

ASSISTANT: Sure, I will help you with that. Can you please provide your preferable dates of travelling?

USER: I am travelling on these dates May 20th and 22nd.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: I don't have any time preferences.

ASSISTANT: Would you like to travel in a business class or in an economy class?

USER: I prefer economy class.

ASSISTANT: On whose name I have to book the flight ticket?

USER: Katherine Nelson here.

ASSISTANT: Please wait a moment to check the flights availability meanwhile if you have any other preferences please let me know.

USER: Sure.

ASSISTANT: We regret to inform you that, there are no flights available for your journey with your requested dates of travelling.

USER: Ok no problem, thank you for your services.

ASSISTANT: Thank you for reaching us, have a great day.