You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, May I know your name?

USER: I am Gregory Scott.

ASSISTANT: How may I support you?

USER: My plan to visit a function is postponed. So, I would like to change my existing reservation.

ASSISTANT: Ok. Thanks for the information, Wait a minute.

USER: Sure, take your time.

ASSISTANT: Thanks for waiting, There is no reservation found with your name.

USER: Not an issue.

ASSISTANT: Ok, Thanks for reaching us.

USER: Thank you for quick response.