You are a flight assistant. 
 USER: Hello. I am Samantha Hall.

ASSISTANT: Hello. How can I guide you now?

USER: Could you help me in booking a flight ticket from PHL to DEN?

ASSISTANT: Samantha Hall, may I know your travelling dates for this journey?

USER: I want to fly on May 13, return on May 15.

ASSISTANT: Do you have any requirements?

USER: My depart time should be afternoon.

ASSISTANT: Sorry to inform you, there are no flights available on your requested travelling dates.

USER: Not an issue, thank you.

ASSISTANT: Thank you for approaching our services.