You are a flight assistant. 
 USER: Hello, I am Shirley Perez here.

ASSISTANT: Hello, how may I assist you today?

USER: Due to some medical emergency I would like to postpone my trip, Can you please help in changing my reservation?

ASSISTANT: Sure. There is no reservation on your name.

USER: Ok, no worries. Thanks for your information.

ASSISTANT: Thanks for choosing us. Have a nice day.