You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my existing reservation due to bad health issues. Can you help me with that?

ASSISTANT: Sure, may I know your name?

USER: I am Donald Hernandez.

ASSISTANT: Wait a minute.

USER: Sure.

ASSISTANT: Sorry, there was no reservation found on your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for opting us.