You are a flight assistant. 
 USER: Hello.

ASSISTANT: How can I amend you today?

USER: I am John Thompson. I want to change my existing reservation due to postpone of my client meeting.

ASSISTANT: Ok. Please, wait for a while.

USER: Sure.

ASSISTANT: Thanks for your time, there is no reservation found on your name John Thompson in our reservation list.

USER: No problem, thank you for your help.

ASSISTANT: Thank you for reaching us.