You are a flight assistant. 
 USER: Hi, I am Anthony Brown.

ASSISTANT: Hello, How may I help you?

USER: I want to change my existing reservation as my exam got postponed.

ASSISTANT: Sure, Please wait a while.

USER: Sure.

ASSISTANT: Thanks for waiting, We did not any reservation with name.

USER: Ok. Thanks for the response.

ASSISTANT: Thanks for contacting us, Have a nice day.