Hello.
user
Hello, how may I oblige you today?
assistant
 I am Gregory Campbell want to change my reservation due to prepone of my meeting. Can you help me in changing?
user
Sure, I will help you with that. Please wait for a moment.
assistant
Ok.
user
Thank you for waiting, there is no reservation found on your name in our database.
assistant
Ok, thank you for your help.
user
Thank you for approaching us.
assistant