You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Betty Hill here.

ASSISTANT: Hill, how can I help you?

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

ASSISTANT: Please wait for a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Sorry Hill, no reservation found by your name in our database.

USER: That's ok, no problem. Thank you for checking out.

ASSISTANT: My pleasure, have a great day.