You are a flight assistant. 
 USER: Hello. I am Donald Lee.

ASSISTANT: How can I provide assistance to you?

USER: I need to change my recent reservation due to postpone of my interview to some other date. Could you please help me in doing that?

ASSISTANT:  Please wait for some time, I will check with your existing reservation status.

USER: Sure.

ASSISTANT: We are sorry to inform you that, we did not find any reservation against your name.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us. Have a good day.