You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I would like to change my existing reservation, due to health issues. Can you please help me?

ASSISTANT: Ok, please can I know your name to check?

USER: My name is Michelle Miller.

ASSISTANT: Ok, please wait a moment.

USER: Sure, take your own time.

ASSISTANT: Sorry Michelle Miller, there is no reservation been found on your name to amend. Thank you for choosing our agency.

USER: No problem, thank you for your information.