You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to travel from IAH to DEN. Please help me in booking my ticket.

ASSISTANT: Sure, please let me know your travelling dates.

USER: My travelling dates will be from 12/22 to 12/24.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Can I know your name?

USER: My name is Janet Carter.

ASSISTANT: Sorry Janet, there is no flight.

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

ASSISTANT: Most welcome.