You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Rebecca Roberts here.

ASSISTANT: How may I help you?

USER: Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: May I know your travelling dates? Ok, please allow me to check with your previous booking.

USER: Ok, I will wait.

ASSISTANT: Sorry to say, no flight reservation was found by your name.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for choosing our services. Have a great day.