You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you for the day?

USER: I am Jennifer Mitchell. Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Sure, Jennifer Mitchell, I am here to help you with that change.

USER: Thank you.

ASSISTANT: Sorry to say, there is no reservation found with your name in our database.

USER: That's fine, thank you for your help.

ASSISTANT: Thank you for approaching us, have a great day.