You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: I am Nancy Walker.

ASSISTANT: How can I serve you?

USER: I need to change my recent reservation due to postpone of my exams. Could you please help me in doing that?

ASSISTANT: Sure, wait for a minute.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no active reservation found on your name.

USER: No worries, thank you for your information.

ASSISTANT: Thanks for approaching us, hope to serve you again.