You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to postpone of my exams, can you help me with that?

ASSISTANT: Sure, I can help you with that. May I know your good name please?

USER: My name is Samantha Lee.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Samantha Lee, there is no active reservation found under your name to do modifications in that.

USER: No problem, thank you for the checking.

ASSISTANT: Thank you for choosing us.