You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I guide you?

USER: Melissa Moore here. Could you please help me in changing my reservation?

ASSISTANT: Sure, I will help you with that. Please wait for a moment, I will check and let you know.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: No issues.

ASSISTANT: Thank you for contacting us.

USER: Thank you for your help.