You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I need to cancel my ticket due to sudden changes which are done in my plan.

ASSISTANT: Sure, I am here to help you.

USER: Ok.

ASSISTANT: May I know your name?

USER: Melissa Hall here.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Ok, not an issue with that. Thank you for serving me.

ASSISTANT: Thank you for choosing us.