You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Dennis Lopez here.

ASSISTANT: How may I guide you?

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

ASSISTANT: Sure, please hold on for a moment, let me check.

USER: Sure, take your time.

ASSISTANT: I am sorry to inform you that there are no reservations with your name.

USER: That's ok, thank you for the help.

ASSISTANT: Thank you, have a good day.