You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I am Nicholas Parker.

ASSISTANT: Glad to meet you Parker.

USER: Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, I am happy to help you with that.

USER: Thank you.

ASSISTANT: Please be hold on for a moment.

USER: Sure, take your own time.

ASSISTANT: Sorry Parker, no reservation found under your name to change.

USER: That's fine, thank you for your help.

ASSISTANT: Most welcome. Thank you for choosing us, have a great day.