You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you today?

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

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can you please share your name?

USER: I am David Baker.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for being patient, there is no active reservation found on your name.

USER: No problem, thank you for the checking.

ASSISTANT: Thank you for approaching us.