You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: My meeting got postponed. So, I would like to change my existing reservation. Please help me in changing my reservation.

ASSISTANT: Ok, please let me know your name, I will check the possibility.

USER: My name is Sarah Garcia.

ASSISTANT: Sorry, there is no reservation showing on this name Sarah.

USER: That's fine. Thank you for the information.

ASSISTANT: Thanks for approaching us.