You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you for today?

USER: I want to change my existing reservation, due to some personal work. Can you please help me with this?

ASSISTANT: I am here to help you in changing your reservation.

USER: Thank you.

ASSISTANT: Can you please provide your name to check the reservation status with your name?

USER: Ok, I am Betty Lee.

ASSISTANT: Sorry to say this Betty Lee, there is no active reservation under your name to change your reservation.

USER: Ok, Thank you for your service.

ASSISTANT: You are welcome, thank you for reaching us.