You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What help can I assist for you?

USER: I want to change my reservation, due to some health problems I am unable to travel those dates, can you please change my reservation?

ASSISTANT: Ok, I am oblige to help you. Can you please tell me your name?

USER: Thanks, my name is Brenda Jones.

ASSISTANT: Sorry Jones, no reservation found on your name in my database.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: Most welcome.