You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Daniel Hernandez.

ASSISTANT: How may I be of your helping hand?

USER: I would like to change my existing reservation, due to an emergency work my planning to meet my colleague has been postponed. Could you please assist me in changing?

ASSISTANT: Sure, wait a while let me check and know you the current status.

USER: Sure.

ASSISTANT: Thank you for your time. Sorry, there is no reservation matching with your name in our portal to make changes further.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for availing us.