You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Gary Lopez from Charlotte.

ASSISTANT: How can I assist you today?

USER: I have planned an event in Las Vegas with my friends so please help me with flight ticket booking.

ASSISTANT: Sure, will you mention your travelling dates please?

USER: Thank you. I need to travel on dates of 05/11 and 05/13.

ASSISTANT: Please provide your airport codes that you want to travel.

USER: Sure, I would like to travel from CLT to LAS.

ASSISTANT: Please give me a moment.

USER: Sure, take your time.

ASSISTANT: Thanks for waiting, there is no flights found under your preferable details.

USER: Oh! It's ok fine, no problem. Anyway, thank you for your time.

ASSISTANT: Welcome, have a great day.