You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be your helping hand?

USER: Stephen Johnson here. Due to inconvenience of my work, I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, I am here to help you.

USER: Thanks for that.

ASSISTANT: Please, wait for a while.

USER: Ok, I will wait.

ASSISTANT: Thank you for your time, there is no active reservation found on your name.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for contacting us.