You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I be of your assistance?

USER: I would like to change my existing reservation which is on the name of Amy Davis as my examination got postponed.

ASSISTANT: Sure, just hold on I will check and let you know.

USER: Ok.

ASSISTANT: Thanks for waiting, we did not found any reservation with this name.

USER: That's ok, thank you for your response.

ASSISTANT: Thanks for choosing us.