You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you for the day?

USER: I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Sure, may I know your name to check the reservation?

USER: My name is Karen Anderson.

ASSISTANT: Sorry, there is no reservation found on your name.

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

ASSISTANT: Thank you for availing us.

USER: Thank you for your service.