You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you today?

USER: I am planning to visit PHL, can you help me to book a flight from SFO?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are 06/17 and 06/19.

ASSISTANT: Do you need any specifications?

USER: I prefer normal cost.

ASSISTANT: Sorry, there are no flight tickets available on your journey dates.

USER: No issues, thank you for your time.

ASSISTANT: May I know you name?

USER: My name is Rebecca Clark.

ASSISTANT: Thank you for reaching our service.