You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Can I have your name please to check your details in our database?

USER: My name is Benjamin White.

ASSISTANT: Sorry to inform you that there is no reservation found on your name to do modification.

USER: Not an issue, thank you for your time.

ASSISTANT: Thank you for reaching us.