You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How could I aid you?

USER: Can you help me to book a flight from PHL to SFO?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travel dates are Nov 24 and 26.

ASSISTANT: Can you please share me your name?

USER: Sandra Roberts here.

ASSISTANT: Do you have any other requirements?

USER: I prefer an economy class.

ASSISTANT: Unfortunately there is no flight found with your given information.

USER: Ok, thank you.

ASSISTANT: Thank you for approaching us.