You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank  you.

ASSISTANT: May I know your good name please?

USER: I am Ryan Walker.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Thanks for your time, there is no active reservation found in your name to change.

USER: No issue.

ASSISTANT: Thank you for reaching us.

USER: Thank you.