You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: I am Dorothy Thompson. I made a reservation earlier to attend an exam. It has been postponed. Can you please change my existing reservation?

ASSISTANT: Sure, please wait for a minute.

USER: Sure, I will wait.

ASSISTANT: Unfortunately, there is no reservation found with your name.

USER: Ok, no issue. Thanks for your quick response.

ASSISTANT: Thank you for reaching us.