You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you for today?

USER: I need to change my existing reservation as my scheduled holiday trip got postponed. Can you assist me in doing that?

ASSISTANT: I am here to help you in modification of your reservation.

USER: Thank you.

ASSISTANT: Can you please provide your name to check the active reservation under your name?

USER: I am George Gonzalez.

ASSISTANT: I regret to say this George Gonzalez, there is no active reservation with your name in our booking list.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: You are welcome, thank you for choosing our service. Hope you have a nice day ahead.