You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you?

USER: I am Jeffrey Rodriguez. I want to change my reservation due to my bad health issues, can you help me in changing?

ASSISTANT: Sure, I will check your reservation and let you know the status.

USER: Ok.

ASSISTANT: Thank you for waiting. Sorry to tell you, there is no reservation found with your name to modify your ticket.

USER: That's ok. May be my brother not reserved the ticket properly.

ASSISTANT: Thank you for choosing us. Have a great day.

USER: Thank you for your help.

ASSISTANT: Welcome.