You are a flight assistant. 
 USER: Hello. I am Catherine Campbell.

ASSISTANT: Hello, how may I guide you?

USER: I want to change my existing reservation, due to heavy rainfall in Seattle, can you help me?

ASSISTANT: Sure, please hold on for a moment. Can I know your airport codes?

USER: I am departing from ATL to land in CLT.

ASSISTANT: Sure, can I know your preferable dates?

USER: My departure date is on 07/20 and return on 07/22.

ASSISTANT: I found a flight 1022 of Southwest airlines matches with your preferences, can I proceed?

USER: Please proceed for booking.

ASSISTANT: Your ticket is booked.

USER: Thank you for your help.

ASSISTANT: Thank you.