Hi. I am William Brown.
user
Hello, how may I assist you today?
assistant
Owing an  emergency want to change my reservation, so can you help me with it?
user
Sure, I can help you best.
assistant
Thank you.
user
Give me a minute, I will check your reservation and get back to you.
assistant
Ok.
user
Thanks for waiting, we did not find any reservation on your name to change.
assistant
That's ok.
user
Thanks for contacting us, have a great day.
assistant
Thank you for the response.
user