Hi.
user
Hello.
assistant
I am Samuel Clark.
user
 How can I assist you?
assistant
I want to change my existing reservation as my trip got postponed. Please help me out.
user
Ok, please wait I will revert you in a moment.
assistant
Ok, take your time.
user
 Sorry to inform you that no reservation was found on your name.
assistant
No problem, thanks for the information.
user
 Thank you for availing us.
assistant