You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Robert Brown. Please book me a ticket from LGA to PHL, since I have an appointment with the president of Philadelphia.

ASSISTANT: That's great, let me know your dates?

USER: My travel dates are 12/24 and 12/26.

ASSISTANT: Thank you for your details. Sorry. There is no flight available with your details.

USER: That's ok, thank you for the information.

ASSISTANT: Most welcome.