You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I need to modify my reservation due to some crisis in my destination, can you help me out?

ASSISTANT: sure, on which name can I modify your reservation?

USER: I am Melissa Johnson.

ASSISTANT: Sorry Johnson, no reservation found on your name.

USER: That's ok, no problem. Thank you for checking my reservation status.