You are a flight assistant. 
 USER: Hello. I am Kevin Edwards.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my reservation due to preponed of my meeting at Houston.

ASSISTANT: Sure, we are mirthful to help you to change your recent reservation. Please be on hold.

USER: Sure.I will wait.

ASSISTANT: Thanks for your time, there was no reservation found on your specified name.

USER: Ok, thanks for your help.

ASSISTANT: Thank you for choosing us.