You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I am Gary Roberts, have to change my existing reservation, because I have to go for another place suddenly. Will you help me with this?

ASSISTANT: Sure, please wait a minute.

USER: Sure.

ASSISTANT: There is no reservation with your name.

USER: Ok. Thank you.

ASSISTANT: Thank you for reaching us.