You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you?

USER: I want to change my existing reservation due to postpone of my board meeting, so can you help me in changing my reservation?

ASSISTANT: Sure, may I know your name please?

USER: My name is Gary Williams.

ASSISTANT: Please be on hold.

USER: Sure.

ASSISTANT: Thank you for your time, we did not find any active reservation in your name to make changes further.

USER: Not a problem, thanks for checking.

ASSISTANT: Thank you for reaching us.