You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: My name is Margaret  Collins. I want to change my previous travelling dates, which is done recently. Can you please help me out in changing?

ASSISTANT: Sure, please wait a moment.

USER: Thank you for considering my request, I will wait for your response.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: Not a problem, anyway thank you for the information.

ASSISTANT: Thank you.