You are a flight assistant. 
 USER: Hello, I am Sarah Taylor.

ASSISTANT: Hello, how can I help you today?

USER: 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: That's not a problem.

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

USER: Thanks for your help.