You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Lisa Thomas, want to travel from DFW to PHL. Please help me in booking my ticket.

ASSISTANT: On which dates you are planning to travel?

USER: Sure, my travelling dates are from 11/15 to 11/17.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

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

USER: It's ok, thank you.

ASSISTANT: Most welcome.