You are a flight assistant. 
 USER: Hi, Sandra Harris here.

ASSISTANT: Hello, how may I address you?

USER: I would like to change my existing reservation. Can you help me in this?

ASSISTANT: Sure, please give me a moment.

USER: Ok.

ASSISTANT: We found a reservation on your name. Will you please provide me your airport codes?

USER: My airport codes are ORD - SFO.

ASSISTANT: When are you planning to travel?

USER: My trip dates are 07/25 - 07/27.

ASSISTANT: How many connections do you need?

USER: I need a single connection.

ASSISTANT: Any other requirements to be met?

USER: No.

ASSISTANT: Ok, there is a Southwest airline with flight number 1004 going on your way with 0 connections and the airfare is 100. Is that okay for you?

USER: Please reserve.

ASSISTANT: Your request for changing reservation has been processed successfully.

USER: Thank you.

ASSISTANT: Thank you for choosing us.