You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: George Lewis here.

ASSISTANT: Nice to meet you Lewis.

USER: I want to book a ticket from PHL to ORD, please check the availability of flight at this route.

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

USER: My travelling dates are from 04/17 to 04/19.

ASSISTANT: Ok, hold on for a moment please. Sorry to say this Lewis, there are no flights on your requested dates. Sorry for the inconvenience provided.

USER: That's ok. Thank you for your service.

ASSISTANT: Welcome.