Hello.
user
Hello, how may I aid you today?
assistant
As my visa interview dates has been changed, so I would like change my existing reservation. Can you help me with it?
user
Sure,  I will be happy to support you. May I know your name for further proceeding?
assistant
I am Mark Thomas.
user
Please give me a moment, let me check your reservation and back to you.
assistant
Sure.
user
Unfortunately, there is no reservation found with your given name.
assistant
No problem, thank you for your assistance.
user
Thank you for approaching us.
assistant