You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I render you at this moment?

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

ASSISTANT: Sure, may I know your good name please?

USER: I am Steven Johnson.

ASSISTANT: Ok, please wait for few minutes.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our records.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.