You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: My name is Dorothy King. I want to change my existing reservation due to postpone of my client meeting.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for your time, there was no reservation found on your name.

USER: Not an issue, thank you for your help.

ASSISTANT: Thank you for choosing us.