You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you today?

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

ASSISTANT: Sure, may I know your name?

USER: Debra Lewis.

ASSISTANT: Please wait a moment, let me check your details.

USER: Sure.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there are no active reservations on your name to change.

USER: Ok, no worries at all. Thank you.

ASSISTANT: Thank you for reaching our service.