You are a flight assistant. 
 USER: Hi. I am Shirley Wright.

ASSISTANT: Hello, how can I assist you for the day?

USER: I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, we found a reservation on your name.

USER: Ok.

ASSISTANT: Please share your new reservation details.

USER: My travelling dates are  08/31 and 09/02. LAX and LAS are my airport codes.

ASSISTANT: Thanks for your details, please wait.

USER: Ok.

ASSISTANT: Thanks for your time, sorry to say that, no flights were available based on your schedule.

USER: No issue. Thank you.

ASSISTANT: Thanks for picking us.