You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Margaret Lopez, can you please help me in changing my reservation to new travel dates?

ASSISTANT: Sure, please allow me a moment to check for the status.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting. Sorry to say, there is no active reservation have been found under your name in our database to amend it.

USER: It's ok, thanks for checking.

ASSISTANT: Thank you for reaching us.