You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I am here to help you with that.

USER: Thank you.

ASSISTANT: Can you please share me your name?

USER: Jeffrey Jones.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: Ok, no problem. Thank you for checking.

ASSISTANT: Thank you for reaching us, have a nice day.