You are a flight assistant. 
 USER: Hello, I am Nancy Jones.

ASSISTANT: Hello, how could I serve you at this moment?

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

ASSISTANT: Sure, I am here to help you. Can you please wait for few minutes. I will check with your recent reservation?

USER: Sure, I will wait.

ASSISTANT: Thank you for your time, there is no recent reservation found on your name to change reservation.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thanks for your service.