You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How shall I help you?

USER: Due to sudden change in my schedule I would like to change my existing reservation. Can you be able to help me in that?

ASSISTANT: Please provide your name?

USER: Myself Ruth Walker.

ASSISTANT: Ok. No reservation found.

USER: Ok, not an issue.

ASSISTANT: Thank you.

USER: Thank you for checking.