You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be of your service?

USER: My exams has been postponed I want to change my existing reservation.

ASSISTANT: Sure, may I know your good name please?

USER: My name is John Clark.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Thanks for being wait. Unfortunately there is no reservation found against your name.

USER: Not a problem, thank you.