You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you today?

USER: Owing an emergence, I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, may I know your name?

USER: My name is Donald Campbell.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Thanks for your time, there was no reservation found on your name.

USER: Ok, no issues. Thanks for the help.

ASSISTANT: Thank you for choosing us.