You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nicholas Campbell.

ASSISTANT: How can I help you?

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

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, no reservation found by your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks.