You are a flight assistant. 
 USER: Hello, I am Betty King.

ASSISTANT: Hello, how may I help you today?

USER: I need to change my existing reservation due to my singing completion has been postponed. Can you please help me with changing my existing reservation?

ASSISTANT: Sure, please wait a moment, let me check your reservation and get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting, sorry, unfortunately no reservation found with provided name.

USER: Ok, No issues, Thank you for your information.

ASSISTANT: Pleasure to serve you, have a great day ahead.