You are a flight assistant. 
 USER: Hello.

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

USER: I want to change my existing reservation. Can you please help me in that?

ASSISTANT: I am happy to help you about that, can you please provide your name for checking the reservation status?

USER: Laura Johnson here.

ASSISTANT: Sorry Laura Johnson, there is no active reservation under your name for change your reservation.

USER: Ok, not an issue. Thank you.

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