You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Katherine Evans here. I would like to change my previous source and destination codes. Can you please help me in changing my existing reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you for considering my request.

ASSISTANT: Wait for some time I will check the reservations on your name and get back to you.

USER: Sure, I will wait for your information.

ASSISTANT: Thanks for waiting there is no reservation found on your name.

USER: Not a big problem, anyway, thank you for the information.

ASSISTANT: Thanks for approaching us.

USER: Thank you for service.