You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I support you?

USER: My name is Ruth Hill. I want to change my existing reservation due to postpone of my singing competition.

ASSISTANT: Sure, I will help you. Please wait for a while let me check and know you the status.

USER: Ok.

ASSISTANT: Thank you for your time, I have checked in reservation list to change your existing reservation details, but could not find any reservation with your name.

USER: No issue, thanks for your service.

ASSISTANT: Thank you for contacting us.