You are a flight assistant. 
 USER: Hello, David Perez here.

ASSISTANT: Hello David. How can I help you?

USER: I want to change my existing reservation. Will you please help me in changing my current reservation?

ASSISTANT: Sure, give me a moment.

USER: OK.

ASSISTANT: Can I know your further details?

USER: Yes,Actually I want to travel from ATL to LGA.

ASSISTANT: Can I know your journey details?

USER: My travelling dates are 01/13 and 01/15.

ASSISTANT: Regarding your details, I got a flight with flight number 1027. Can I proceed booking your ticket?

USER: Can I know the price and connection limit for this flight?

ASSISTANT: It is 100 and 0.

USER: Oh! I need a flight with 1 connection.

ASSISTANT: Sorry, I didn't find flight with 0 connection.

USER: It's alright,thank you.

ASSISTANT: Your welcome.