You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I have a concert to attend at San Francisco. Can you help me in booking a ticket from Boston?

ASSISTANT: Sure, I will help you to book a ticket. Please provide me your travel dates.

USER: I am planning to travel on dates 04/26 and 04/28.

ASSISTANT: May I know your travel dates? Airport codes?

USER: The airport codes are BOS and SFO respectively.

ASSISTANT: May I know your name to proceed further?

USER: My name is Shirley Martinez.

ASSISTANT: Sorry, I cannot find any flight with your travel dates.

USER: That's fine, I will find other way out. Thank you for the information.

ASSISTANT: It's my pleasure.