You are a flight assistant. 
 USER: Hello, I am Helen Moore.

ASSISTANT: Hello, how may I aid you today?

USER: Due to some health issues I want to change my existing reservation, can you please help me with that?

ASSISTANT: Sure, please wait I will check whether your reservation existed or not.

USER: Sure, I will wait for you.

ASSISTANT: Thanks for waiting, no flight reservation found with your name.

USER: Ok, no issues, thanks for your information.

ASSISTANT: Thanks for approaching us.

USER: Thank you.