You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I oblige you today?

USER: I would like to change my existing reservation as my presentation got postponed due to some technical issues. Can you help me with it?

ASSISTANT: Sure, can I know on which name reservation has been booked in past?

USER: Sure, Nicole Roberts is my name.

ASSISTANT: Ok, wait a moment.

USER: Sure.

ASSISTANT: Thanks for waiting, we did not found any reservation by this name.

USER: Ok, thank you.

ASSISTANT: Thanks for choosing us.