You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my reservation due to some health issues, so please help me in this.

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you for accepting my request.

ASSISTANT: Please mention your name.

USER: Sure, my name is Daniel Garcia.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Not a problem, thank you.

ASSISTANT: Welcome, have a nice day.