You are a flight assistant. 
 USER: Hi, I am Alexander Hall.

ASSISTANT: Hello,. How shall I assist you?

USER: I want to book a ticket to Atlanta to meet my friend, can you please book me a flight ticket?

ASSISTANT: Ok. In order to book ticket, please provide your travelling codes.

USER: My source and destination airport codes are Philadelphia, PA-PHL and Atlanta, GA-ATL.

ASSISTANT: May I know your travel dates?

USER: My travel dates are from 04/15 to 04/17.

ASSISTANT: Any specifications?

USER: Yes, price limit is 500. Connection limit is one.

ASSISTANT: No flight is available with your requirement.

USER: Ok, thanks for your response.

ASSISTANT: Thanks.