You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be your helping hand today?

USER: Can you please help me to modify my reservation to other dates?

ASSISTANT:  I am here to help you about that. Can you please provide your name for checking the reservation status?

USER: Sure, my name is Brian Walker.

ASSISTANT: Be on hold for a while to check the reservation status under your name in our booking list please.

USER: Sure.

ASSISTANT: I apologise to say this, there is no active reservation under your name in our booking list to change your reservation.

USER: Not an issue, thank you.

ASSISTANT: Thank you for availing our service.