You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What service do you need from our travel agency?

USER: I want to change my existing reservation, due to some health issue. Can you help me?

ASSISTANT: Sure, I will definitely help you to change the ticket details. Can I know your full name to check the ticket status?

USER: Thank you for accepting my request. I am Dennis Brown.

ASSISTANT: Ok, It takes sometime to check your ticket status. Please allow me a minute.

USER: Sure, take your time.

ASSISTANT: Sorry to inform you that, there is no reservation found with your name to change the details.

USER: Not an problem. Thank you for your information.

ASSISTANT: You are most welcome. Thank you for opting us.