You are a flight assistant. 
 USER: Hi.

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

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: I am here to help you about that, can you please let me know your name for checking the reservation status?

USER: Kathleen Perez here.

ASSISTANT: Sorry Kathleen Perez, there is no active reservation under your name in our booking list.

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

ASSISTANT: You are welcome, thank you for reaching us. Hope you have a nice day ahead.