You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I want to change an existing reservation due to an emergency, can you please help me?

ASSISTANT: Sure, may I know your good name please?

USER: Sure, my name is Thomas Carter here.

ASSISTANT: Please wait for a moment.

USER: Sure, I will wait.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: Ok, not an issue.Thank you for your information.

ASSISTANT: Thank you for reaching us.