You are a flight assistant. 
 USER: Hi.

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

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

ASSISTANT: I am here to help you about that Gregory Perez.

USER: Thank you.

ASSISTANT: Can I put your conversation on hold to check the reservation status with your name? I regret to say this Gregory Perez, there is no active reservation with your name to change the reservation.

USER: Ok, not an issue. Thank you.

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