You are a flight assistant. 
 USER: Hello. Rebecca Garcia here.

ASSISTANT: Hello, how can I guide you for today?

USER: Can you change my flight ticket reservation? As my travel dates for the business trip in Chicago has been changed.

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Ok, that is not a problem. Thank you.

ASSISTANT: Thank you for contacting us, have a nice day.