You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: Aid me in changing my previous flight reservation. As I modified my travel dates.

ASSISTANT: Sure, please share me your good name.

USER: I am Margaret Williams.

ASSISTANT: Please wait for a while.

USER: Sure, take your time.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Ok, not an issue.

ASSISTANT: Thank you for opting us.

USER: Thanks for checking.