You are a flight assistant. 
 USER: Hello, my name is Ronald Allen.

ASSISTANT: Hello. How may I render you today?

USER: I would like to change my existing reservation as my plan to go on a trip got postponed. Can you help me with it?

ASSISTANT: Sure, just a moment I will check the reservation list.

USER: Sure.

ASSISTANT: Thanks for waiting, sorry to say this there is no reservation found on this name.

USER: It's ok, thank you for the information.

ASSISTANT: you're welcome. We are glad to serve you again.