You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Matthew White, want to travel from IAH to PHX. Please help me in booking my ticket.

ASSISTANT: Sure, may I know your travelling dates please?

USER: My travelling dates are from 10/20 to 10/22.

ASSISTANT: Sorry Matthew, there is no flight available as per your requested dates.

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

ASSISTANT: Most welcome.