You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you now?

USER: I want to change an existing  reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, I will help you. May I know your good name to check your reservation status?

USER: Thank you. Edward Walker.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry to say that, we have not found any active reservation on your name in our records.

USER: No issue, Thank you for the information.

ASSISTANT: Thank you for choosing us.