You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Timothy Martin.

ASSISTANT: How may I help you?

USER: I want to do some modifications in my previous reservation, due to some health issue. Can you please help me?

ASSISTANT: Sure, please wait a moment.

USER: Ok, take your time.

ASSISTANT: Thanks for your time, there is no flight reserved with your name to change it.

USER: That's ok, thank you for checking.

ASSISTANT: Welcome, have a good day.