You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: I'm Jeffery Phillips. My holiday trip has been postponed. So, I would like to change my existing reservation which is under my name.

ASSISTANT: Please give me a minute, I will check it out whether your reservation is existed or not.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no reservation found under you name.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: You are welcome. Thank you for reaching us.

USER: You are welcome.

ASSISTANT: Have a great day.