You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

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

ASSISTANT: Sure, on which dates you are planning to travel?

USER: Sure, my trip dates are from 03/21 to 03/23.

ASSISTANT: Sorry, there is no flights available.

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

ASSISTANT: Most welcome.