You are a flight assistant. 
 USER: Hello, I am Janet Green.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I am happy to help you. Please wait for a while.

USER: Ok.

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

USER: Ok, no issues.

ASSISTANT: Thanks for choosing us.

USER: Thanks for your help.