You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Dorothy Smith here.

ASSISTANT: How may I help you today?

USER: Can you book a flight ticket for my airport codes that is from PHL to DEN?

ASSISTANT: Ok, I am here to help you with that. Can I know your planned trip dates?

USER: The trip dates are from May 03 to May 05.

ASSISTANT: Do you have any other requirements?

USER: No.

ASSISTANT: Can I know your good name?

USER: I am Dorothy Smith.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: We are regret to inform you that, there are no flights available based on your trip dates.

USER: Not a problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.