You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Nicolas Walker.

ASSISTANT: How may I help you?

USER: I need to amend my reservation, can you help me out please?

ASSISTANT: Sure, please wait a moment. Walker, no reservation has been found on your name.

USER: That's ok, no problem. Thank you for your help.

ASSISTANT: Thank you for choosing us.