You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I serve you?

USER: I want to change my flight reservation as my trip got postponed, can you please help me?

ASSISTANT: Sure, I will render you. Please provide the name on which ticket was reserved.

USER: Sure, my name is Christine Mitchell.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry, there is no reservation existing on your name.

USER: No problem, thank you for checking.

ASSISTANT: You are welcome, have a nice day.