You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what help are you seeking form our agency side?

USER: Can you please help me in changing my existing reservation which is done by me last week?

ASSISTANT: Ok, may I know your name to check with your previous booking please?

USER: Sure, Nicole Lopez here.

ASSISTANT: Please allow me to check for a moment.

USER: Sure, I will wait for your response.

ASSISTANT: Nicole Lopez, there is no reservation found by your name in our data base. Sorry for the inconvenience.

USER: Ok, no issues.

ASSISTANT: Thank you for approaching our agency regarding your requirement.

USER: Thank you for your information.

ASSISTANT: Have a nice day.