You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Emily Wilson here.

ASSISTANT: What kind of assistance you are looking for?

USER: I would like to book a ticket from PHL to DCA, can you please help me with that?

ASSISTANT: Sure, I will help you. May I know your travelling dates?

USER: The travel dates are from 12/04 to 12/06.

ASSISTANT: Do you have any specifications?

USER: Price limit is 500.

ASSISTANT: There are no flights available under the range of 500.

USER: That's ok, thank you for your help.