You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you?

USER: I am Patrick Hill, want to travel from ORD to SEA.

ASSISTANT: May I know your trip dates?

USER: My travelling dates are from 05/19 to 05/21.

ASSISTANT: Sorry, there is no flights available.

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

ASSISTANT: Most welcome.