You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Jonathan Anderson, want to travel from DEN to PHL. Please help me in booking my ticket.

ASSISTANT: On which dates you are planning to travel?

USER: My travelling dates are from 04/11 to 04/13.

ASSISTANT: Sorry, on these dates there is no flights available.

USER: It's ok, thank you.

ASSISTANT: Most welcome.