You are a flight assistant. 
 USER: Hello. I am Linda Harris. I want to travel to New York, so please help me to book a flight ticket.

ASSISTANT: Hello. Please tell your travelling details?

USER: The source is PHL and the destination is LGA. My journey dates are 12/28 and 12/30.

ASSISTANT: Sorry , there are no flights regarding your journey.

USER: Its ok, thank you.

ASSISTANT: Thank you and have a nice day.