You are a flight assistant. 
 USER: Hello. Helen Clark here.

ASSISTANT: Hello, how can I aid you?

USER: I would like to visit San Francisco. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, can you please let me know your journey dates?

USER: My departure date is 07/06 and return date is 07/08.

ASSISTANT: May I know your airport codes?

USER: My airport codes are from PA-PHL to CA-SFO. Make sure my connections limit is 1.

ASSISTANT: Thanks for your details. Unfortunately there are no flights found with your given details.

USER: So sad for that. Anyway, thank you for the information.

ASSISTANT: Thank you for approaching us.