You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am John Miller, want to travel from IAH to LAS. Please help me in booking my ticket.

ASSISTANT: Sure, can you tell me your trip dates?

USER: Sure, my trip dates are from 06/22 to 06/24.

ASSISTANT: Do you have any other requirements?

USER: My return time should be in the afternoon and also I need a connecting flight.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

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

ASSISTANT: Most welcome.