You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, I can help you and can I know your name please?

USER: My name is Sarah Thompson.

ASSISTANT: Please wait for a moment.

USER: Sure.

ASSISTANT:  Thank you for waiting, I have checked in reservation list to change your ticket but could not find any reservation with your name.

USER: Ok, not a problem. Thank you for notifying me.

ASSISTANT: You are most welcome and thank you for reaching us.