You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Paul Thomas.

ASSISTANT: How can I assist you?

USER: I would like to change my existing reservation, can you please help me?

ASSISTANT: Sure, please wait moment.

USER: Ok.

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

USER: Ok, no worries at all.

ASSISTANT: Thank you for approaching us.