You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you at this moment?

USER: I am looking for a direct flight in my journey. Will you please help me with booking a flight ticket?

ASSISTANT: May I know your planned journey dates?

USER: My planned journey dates are July 15 and July 17.

ASSISTANT: Can you help me with your airport codes?

USER: Sure, my source and destination codes are PHL and SFO.

ASSISTANT: Is there any connection limit?

USER: I am looking for a direct flight in my journey.

ASSISTANT: Any more requirements?

USER: No, thank's for asking.

ASSISTANT: May I know your good name?

USER: Sure, Catherine Mitchell.

ASSISTANT: There were no flights found with your required dates to travel.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for choosing us.