You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Because of some business meeting postpone I want to change my existing reservation. Can you please help me in this condition?

ASSISTANT: Sure, just provide me your name for further process.

USER: Sure, I'm Gary Carter here.

ASSISTANT: Gary Carter, I'm sorry to inform you hat there is no reservation found by your name.

USER: That's fine.

ASSISTANT: Thanks for contacting us. Have a great day.

USER: You are welcome.