You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Sandra Adams.

ASSISTANT: Sandra Adams, how can I aid you today?

USER: I want to change my existing reservation due to some health issue, can you please help me with this?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Hold on for a moment. Let me check.

USER: Sure.

ASSISTANT: Sorry Sandra Adams, there are no flights reserved on your given name formerly.

USER: No problem, thanks for your information.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.