You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Cynthia Baker here. As my grand mother got sick , I want to change existing reservation.

ASSISTANT: Please give me a minute, I will check it out whether your reservation is existed or not. Sorry, there is no reservation found under your name.

USER: That's ok.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your help.

ASSISTANT: You are welcome.