You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation,will you help me in that?

ASSISTANT: Sure. To check reservation I need your name.

USER: Sure,my name is Pamela Green.

ASSISTANT: OK, please wait a moment.

USER: OK.

ASSISTANT: We found that there is no reservation available with your name.

USER: OK,no problem. Thank you so much.

ASSISTANT: Thank you for opting us.