You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please help me to change my existing reservation as I have changed my trip plan?

ASSISTANT: Sure, I am here to help you for this. May I know your name please?

USER: My name is Justin Martinez.

ASSISTANT: Please wait for a while, let me check your reservation status in our records.

USER: Ok.

ASSISTANT: Sorry to intimate that, no reservation is found with your credentials.

USER: No problem, thank you for your information.

ASSISTANT: Thank you very much for contacting our agency.