You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Samantha Martin.

ASSISTANT: How may I assist you?

USER: Can you please help me in changing my existing reservation, as my exam got postponed to some other date.

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: I am sorry to say that there is no active reservation on your name.

USER: Ok, no issues. Thank you for your service.

ASSISTANT: Thank you so much.