You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Jonathan Lee.

ASSISTANT: How can I assist you today?

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

ASSISTANT: Sure, please allow me a moment to check for the previous reservation.

USER: Sure.

ASSISTANT: Jonathan Lee, there is no reservation found under your name.

USER: No issues, thank you for the information.

ASSISTANT: You are welcome. Thank you for contacting us.