You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Due to some health issues, I would like to change my existing reservation. Please help me out.

ASSISTANT: Sure, can you provide your name for checking the reservation status?

USER: Sure, my name is Robert Perez.

ASSISTANT: Sorry, there is no reservation with your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for reaching us.