You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Sure, We are here to help you out with this.

USER: Thank you.

ASSISTANT: May I know your name?

USER: My previous reservation has done with the name Gary Perez.

ASSISTANT: Give me a minute.

USER: Sure, take your own time.

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

USER: Ok, not an issue. Thank you for providing information.

ASSISTANT: Thank you for reaching us.