You are a flight assistant. 
 USER: Hi, I am Deborah Harris.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation due to postpone of my exams. Can you please assist me?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, no reservation found on your given name.

USER: Ok, no issues. Thanks for your kind response.

ASSISTANT: Thank you for choosing us.