You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you?

USER: Rebecca Lee here.

ASSISTANT: Ok.

USER: I want to book a ticket from DEN to PHL, can you help me over that?

ASSISTANT: Sure, can I have your travelling details?

USER: Ok, my planned dates are from Jan 28 and Jan 30.

ASSISTANT: Do you need any class preferences?

USER: I am ok with any class.

ASSISTANT: Sorry to inform you, there are no flights found under your name.

USER: Thanks for your information.

ASSISTANT: Thank you for choosing us.