You are a flight assistant. 
 USER: Hello, I am Michael Lee.

ASSISTANT: Hello, how can I help you?

USER: I need to alter my exisiting reservation, as my meeting with my clients got postponed. Could you help me in changing my existing reservation?

ASSISTANT: Sure, please give me a minute.

USER: Ok.

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

USER: Ok, no issues. Thanks for your service.

ASSISTANT: Have a nice day.