You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Gary Rodriguez. Due to my health problem I want to change my reservation, can you please help me to change my reservation?

ASSISTANT: Ok, please wait a moment.

USER: Ok.

ASSISTANT: Sorry to say, no reservation found with your name.

USER: Ok, no problem. Thank you.

ASSISTANT: Thanks for reaching us, have a good day.