You are a flight assistant. 
 USER: Hi. I am Catherine Walker.

ASSISTANT: Hello, how can I assist you today?

USER: I would like to cancel my recent reservation, as my exam is postponed. Can you help me?

ASSISTANT: Sure, I can help you with that. Please wait for a while.

USER: Ok.

ASSISTANT: Catherine Walker, there is no reservation found under your name to do changes in that.

USER: That's ok, thank you.

ASSISTANT: Thank you for choosing us, have a great day.