Hi, I am Gregory Walker.
user
Hello, Gregory Walker. How can I assist you today?
assistant
Owing an emergency I had to request  change an existing reservation. Can you help me out with this?
user
Sure, I am here to help you. Please, wait a minute I will check and revert you.
assistant
Sure.
user
Sorry, I found no reservation in your given details.
assistant
Ok, thanks for your information.
user
Thank you, for opting us. Have a nice day.
assistant