You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Gregory Rodriguez.

ASSISTANT: How may I assist you?

USER: Can you please change my existing reservation as my plan to go for holiday trip got postponed?

ASSISTANT: Gregory Rodriguez, please allow me to check with your booking.

USER: Ok, I will wait for your response.

ASSISTANT: No reservation was found by your name.

USER: It's ok, not an issue.

ASSISTANT: Thank you for choosing our services.

USER: Thank you for your response.

ASSISTANT: Have a nice day.