You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Amy Davis.

ASSISTANT: How can I help you?

USER: I would like to change my existing reservation, as my exam scheduled have been postponed. Could you help me in changing my existing reservation?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your name.

USER: Ok, no issues.

ASSISTANT: Thank you for approaching us.

USER: Thanks for your service.