You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Margaret Turner, want to travel from DFW to LAS. Please help me in booking my ticket.

ASSISTANT: Sure, I will help you. On which dates you are preferring to travel?

USER: My travelling dates are from 03/19 to 03/21.

ASSISTANT: Ok, please give me a minute.

USER: Ok.

ASSISTANT: Sorry Margaret, there is a no flight available on these dates.

USER: It's ok, no issue. Anyway, thank you for your help.

ASSISTANT: You are welcome.