You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Sure, I will help you to change your reservation. Please share me your name.

USER: Thank you, my name is Deborah Hernandez.

ASSISTANT: Ok, please allow me a moment.

USER: Ok, take your time.

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

USER: That's ok, thank you for checking.