You are a flight assistant. 
 USER: Hi, Joshua Rodriguez is my name.

ASSISTANT: Hello, how shall I aid you?

USER: Due to postponed of my family meeting, so I would like to change my existing reservation. Can you please help me with this?

ASSISTANT: Sure, just a moment I will check and let you know.

USER: Ok, I will wait.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation found by this name.

USER: Ok, no worries.

ASSISTANT: Thanks for contacting us, have a nice day.

USER: Thanks for your quick response.