You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, welcome to our agency. How may I assist you?

USER: Can you help me in changing my existing reservation? As I have an urgent meeting to attend.

ASSISTANT: Sure, may I know your name please to validate your reservation in our database?

USER: Well, my name is Patrick Nelson.

ASSISTANT: Nelson, please wait for a minute. I will check the status of your reservation.

USER: Ok, take your time.

ASSISTANT: Nelson, I had found nothing to substantiate your reservation.

USER: I guess there is a problem occurred while booking the ticket. Anyways, thank you for the information.

ASSISTANT: Thank you for utilising our services.