You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

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

ASSISTANT: Sure, please allow me a moment.

USER: Ok, I will wait.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

USER: Anyway, thanks for the information.

ASSISTANT: You are welcome, have a great day.