You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello.

USER: I am Eric Williams.

ASSISTANT: How can I oblige you?

USER: I want to change my existing reservation as my trip plan was postponed. Will you help me in changing my reservation?

ASSISTANT: Sure. Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Thank you for quick service.

ASSISTANT: Thank you for opting us.