Hi.
user
Hello.
assistant
I am David Williams.
user
 David Williams. How may I help you?
assistant
I need to change my reservation as my plan to go for shopping got postponed. Can you help me?
user
Sure, would you prefer giving a moment.
assistant
Sure.
user
Sorry, there is no reservation by the name David Williams.
assistant
That's Ok, thanks for your response.
user
Thank you for approaching us.
assistant