You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, may I know your name to check the reservation?

USER: Jerry Jackson here.

ASSISTANT: Ok, please be on hold.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found with your name in our database.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for opting us.